fault tracing
Short Description
fault tracing strategy...
Description
Fault tracing strategy BEA Student booklet
Foreword
Contents
This training package cover the fault tracing strategies to be applied to Volvo buses equipped with BEA multiplex electrical systems. This training package makes no claim towards describing any exact fault tracing strategy, but is general in terms and aims aim s to give the student suggestions towards fault tracing methods. Since these fault tracing strategies are general, similar methods can be applied when fault tracing any multiplex electrical system on a Volvo bus. The main example used in this training package is based on the MID 128, i.e, the engine control unit.
1 Dri Driver ver inte intervi rview ew and and test test drivi driving ng .... ....... ....... ....... ...... ..... .. 3 2 Re Read adin ing g fault fault code codes s MID, MID, PID/P PID/PPI PID D ... ..... .... ..... ..... .. 4 3 Rea Readin ding g faul faultt code codes s SID/ SID/PSI PSID, D, FMI .... ....... ...... ...... ... 6 4 How is a faul faultt code code set set? ? ... ...... ....... ....... ...... ....... ....... ....... ....... ... 7 5 MID numbe numberr .... ....... ....... ....... ....... ....... ...... ....... ....... ....... ....... ...... ....... ....... ..... 8 6 MID manu manual, al, list list of of conten contents..... ts........ ...... ....... ....... ....... ....... ... 9 7 MID man manual ual,, system system descr descript iption ion,, specificatio specif ications ns ....... .............. .............. .............. .............. ............. .......... .... 10 8 MID manu manual, al, tool tools s ....... ............. ............. .............. .............. ............ ..... 11 9 MID manu manual, al, cont control rol unit desi design gn and function func tion ...... ............. .............. ............. ............. .............. ............. ............. ......... 12 10 MID manual, manual, parame parameter ter list list ...... ............. .............. ........... .... 14 11 MID manua manual, l, pin-out pin-out,, connecto connectors rs ....... ............. ........ .. 15 12 MID manual, control control unit functions, electrica elec tricall diag diagram ram ....... .............. .............. .............. .............. .......... ... 16 13 MID manu manual, al, func function tional al diso disorder rders s ...... ............. ......... 17 14 MID manua manual, l, FMI-tab FMI-table le ...... ............. .............. .............. ........... .... 18 15 MID manual, manual, description description of measurements measurements 19 16 MID manual, manual, fault fault code table............ table................... .......... ... 20 17 Cont Control rol unit unit and connec connectors tors,, identifica identification tion . 21 18 Faul Faultt code code MID 128 PID 175 175 ....... ............. ............. ......... .. 22 19 Connecting up the adapter and and break-ou brea k-outt box ....... .............. .............. .............. .............. ............. .......... .... 23 20 Fault code MID MID 128 PID 175, 175, measurement measure ments s ...... ............. .............. .............. .............. .............. ....... 24 21 Supe Superimp rimposin osing g temp template lates s ...... ............. .............. ............. ...... 26 22 Meas Measurem urement ent directl directly y on pins pins ...... ............. ............. ........ 27 23 Statu tatus s test............ test................... .............. .............. .............. .............. .......... ... 28 24 Faul Faultt codes, codes, activ active-in e-inactiv active e ...... ............. .............. .......... ... 29 25 Conn Connector ectors, s, sockets sockets and and pins ....... .............. ............ ..... 30 26 SAE J170 J1708, 8, SID SID 250 250 ....... .............. .............. .............. ............. ...... 31 27 Appl Applicat ication ion erro errorr ...... ............. .............. .............. .............. .............. ....... 32 28 SAE J1939 J1939,, PSID 200200-215 215 FMI 9 ....... ............. ........ .. 33 29 Cont Control rol unit, unit, checks checks ....... .............. .............. .............. .............. ....... 35
in le t i n u l l e c e B B u s e s v i c S e r v 7 ) N o o u p G r o
Service Manual Buses
a g e o n P s i o V e r s
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Section 37 Edition 01
s g h t s L i g Electrical system B12B o n 2 s i o e r s Multiplex electrical system. Version 2 m. V e e t s s y
io n a t i o p o r a r p s C o w e d e n B u s C o B v o g , S r g, V o l v e b o e G ö t
ic a l r i c h e n t h i n e c t r l e io n s e a c h i o e x e ip l e r i p u n c t u ig h t f e d u n d e M u l t t l l l l i g a b b i i s s r l c s a n d e s i s s d e e ) h t i o e m o d u l e io n y s t e u n c o l M l i g n g s o n t r r o h f u h n i n t ig t C r e g h t n L i g g h t d i f f f e fe e n ( L i g
S e er r v i v ic e c M e a n nu a u l a l B u s s e es s S
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cc
1
3/5
11:45 am 12345 km
Dri rive verr in inte terv rviiew an and d tes testt dri drivi vin ng
An important point is to start with a driver interview; to be able to determine when the fault occurred, what the symptoms where, the type of driving situation, if it was night ti me (heavy power consumption), consumption), if it was raining (dampness in circuits) etc. Read off any fault codes. Delete any inactive fault codes before performing performi ng a test drive. It is an advantage if the normal driver can partake in the test drive, so that a more complete idea of the symptoms can be gathered. Read off and record fault codes. Compare re-occurring fault faul t codes, Active-Inacti Active-Inactive? ve? With all fault tracing in the BEA system, it is advisable to use the service literature available, such as electrical diagrams, MID manuals and the functional diagr am that handles the circuit from where the fault originates. ori ginates. The MID manuals and functional diagrams diagr ams can be found in the function group in question, i.e. engine group 2, brakes group 5, air suspensio suspension n group 7, etc. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Global Training GT2300113eng
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Reading fault codes MID, PID/PPID
Fault codes can be read out directly from the bus display under the diagnostic menu, or by using diagnostic tool VCADS-pro. Each fault code has a short display text that states the component/function effected, this menu also shows if the fault is active/inactive and how many times the fault has occurred. Pressing enter in this menu reveals a numeric code. The numeric fault code comprises three types of identification; MID, PID /PPID, SID/PSID and FMI. MID, PID, SID and FMI follow a fixed SAE standard, J1708. PPID and PSID follow a special Volvo standard. In this menu you can also read out at which times and dates t he fault code occurred for the first and last times. If you enter a password, you can also delet e inactive fault codes from this menu. MID (Message Identification Description), is an SAE standard that shows which control unit is sending a signal/value. PID (Parameter Identification Description), is a SAE standard that shows which component is sending a signal/value. PID is an analogue value, for example oil pressure or coolant temperature. The engine control unit uses these values to optimize fuel injection, etc, but it also makes them available on the CAN link J1939 and the info link J1708. This information must be analogue since these fault messages can both indicate faul ts in circuits and values that are high/low but still within tolerance, (e.g. high coolant temperature). This type of fault code is separated by FMI information. More about FMI further on in the training package. PPID (Proprietary Parameter Identification Description) has the same characteristics as PID but is built up according to a Volvo standard. Global Training GT2300113eng
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These analogue values can be read off using VCADS-pro tests 28407-8 Sensor value check, engine running and 28408-6 Sensor value check, engine stationary. This test applies to the engine, but other control units also use PID/PPID. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Global Training GT2300113eng
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SID 22
MID 128
PID 190
753A
3
Reading fault codes SID/PSID, FMI
SID (Subsystem Identification Description), which is an SAE standard, is an on/off signal i.e. a digital signal, e.g. the signal that opens the solenoid on the engine’s injectors. SID 22 for example, is a digital fault message indicating that a fault has occurred in the engine’s flywheel speed circuit. The information about the engine’s flywheel speed is however an analogue (var iable) value, PID 190, which the engine control unit uses to determine the engines firing point etc. The signal is also made available on the CAN links and is used by the tachometer and for diagnostics with VCADS-pro etc. If a fault occurs in this circuit, the engine control unit will however set fault code SID 22, “not functioning”, a digital message which is sent out on J1708 to the bus display (BIC). This SID is normally in the “off” condition and is only activated to “on” if a fault occurs. PSID (Proprietary Subsystem Identification Description), has the same characteristics as SID but is built up in accordance with a Volvo standard. FMI (Failure Mode Identifier), which is the third part of the message, is an SAE standard that shows the type of fault in question, e.g. FMI 5 which means abnormally low current or open circuit. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Global Training GT2300113eng
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4.93V
0.11V
-40°
103° 150°
F45
1 756
6150
2
1
U (V) 5,0
2
4,5 4,0 3,5 3,0 2,5
3 J1708
2,0 1,5 1,0 0,5 0
50
100
150
T (o C)
6072
4
How is a fault code set?
The engine’s coolant sensor “756” receives a 5V supply from the engine control unit (EECU). The current passes through a 1.2 Kohm resistance, to the sensor ’s connector pin 1. The current passes through the sensor whereby the voltage is reduced and is grounded, via pin 2, in the control unit. The hotter the engine/sensor is, the larger the voltage drop across the sensor (refer to the graph). The voltage is read off by the control unit detector (1) and forwarded to the AD (analogue/digital) converter (2) which converts the analogue voltage to a digital value. This value is sent as message to the control unit processor (3), which uses this value together with other sensor information and engine software, to optimize the engine’s running. The value is also made available on J1708 via PPID119 and can be read on the instrument panel temperature gauge. The resistance (Voltage divider) has several functions, if for example the sensor should be short circuited, or the supply wire become grounded, the resistance works as a kind of fuse. The system also uses it as a reference to the incoming value. If the sensor’s value is greater than 5V or lower than 0V, fault code MID 128, PID 110, FMI 3 or 4 is set, which means that it is an unrealistic value and indicates an electrical fault rather than a fault in the cooling system. With this type of fault, the yellow information lamp also lights and the systems software causes the coolant temperature gauge to show 0°C. When the temperature reaches 102°C (Approx. 0.11V through the sensor), the following occurs; The yellow information lamp lights and a warning is shown on the display, the engine power is gradually reduced until at 107°C, only 50% remains. If the engine temperature increases further, the red stop lamp lights, the central warning lights, the buzzer sounds and fault code MID 128, PID 110, FMI 0 are activated. Global Training GT2300113eng
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G s e 0 2 R e l e a ) E E C U n i t ( n t r o l U o C e g i n 2 8 E n M i d 1
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2 0 0 02 6 5 5
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5
MID number
Every control unit connected to the BEA system network has a MID number according to the SAE standard, e.g, MID 128 which is the engine control unit (EECU). This means that all numeric fault codes start with a MID number. This makes it possible to deduce from which circuit the fault originates when reading the code on the bus display or VCADs-pro. Each control unit has its own manual, where the complete fault code can be found. The manual provides information about probable faults, control unit pin configuration, suitable tests in VCADS-pro, etc. These MID manuals can be found in their respective function groups; MID 128 in function group 28, MID 136 (brakes) in group 59, MID 130 (gearbox) in group 43, etc. There are also check lists for most of the control unit’s inputs and outputs as well as functional diagrams for certain selected functions. This information is also found in the relevant function group. More about these documents further on in the training package. MID-numbers that can be found in Volvo bus multiplex electrical systems; MID 128 Engine control unit (EECU) MID 136, Brake control unit (EBS/ASR) MID 144 Vehicle control unit (VECU) MID 222 Retarder control unit (RECU) MID 223, Gear shifter control unit (GECU)
MID 130 Transmission (TECU) MID 140, Display (BIC) MID 150, Air suspension control unit (ECS) MID 216 Control unit outer lighting (LCM) MID 249, Body builder control unit (BBM)
The number of control units and their functions can vary depending on the specification of the bus. Global Training GT2300113eng
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C on t e nt s
G en e r al ............ ............ M ul ti pl e ............ xe d e l ec ............. tr i ca l sy st ............ e ............ m ........ S pe c i fi ca ............ .. ............ t i on s ... ............. .. .. .. .. .. .. .. .. 3 ............ ............ E ng i ne .. .. c on ............. ............. t r ol u .. ni t, E EC .. .... 3 ............ U ...... ............ T oo l s ... .. . .. .. .. .. .. ............ ............ ............ ............ ........... ............ S pe .. 4 .. ci a .. .. .. .. l t oo .. .. . .. .. .. ............ l s ... ............ ............ .. ............ .... 4 ............ ............. D e si g n .. .. .. .. .. .. .. ............ ............ and F un ............ ............ c ti on ..... .. 5 .. .. .. .. .. .. .. .. ............ ............. M al fu n c t io .. .. .. ... 5 n .... ............. ............ ............ M I D 1 2 8 .. .. .. .. ............ ............ F au l t c o ............. ........... d es .... F au l t c o .. 6 .. .. ............. ............ de t r ou .. b .. .. .. .. .. .. l .. e .. ............ sho o ti n ............ M I D 1 2 8 g ........ ............ ...... 14 P I D 2 1 .. .. .. .. .. .. ............ ............ S en so r t e M I D 1 2 8 ............ ......... 1 mp e r a P I D 2 6 t u re ............. 4 F , c a o n s p ee ............ M I D 1 2 8 nt ro l u d n .. i p t .. 17 P I D 4 5 er c e ............. n t .... P r eh ............ e at er ............ M I D 1 2 8 .. ............ .... 2 0 st at us .. P I D 4 9 ............ ............. ABS c o M I D 1 2 .. .. .. n .. .. t ro ...... 2 1 l s t at u ............ 8 P I D 5 s ........ ............ 0 AC -s y M I D 1 2 8 .. .. s .. .. t ............ ......... 2 em , st a P I D 5 1 ............. 2 t u s / re q u T hr ot t l e .. M I D 1 2 8 e .. s .. t .. . .. p .. .. o .. .... 2 3 si ti on ............ P ID ...... 8 4 R ............ ............ oa d s p e M I D 1 2 8 .. .. .. .. ed ....... ............ ..... 2 4 P I D 8 5 ............ ............ C r ui se c M I D 1 2 8 .. .. .. .. .. ............ on t r ol s ....... 2 5 P ID 9 1 A ............ t at us .. c c .. .
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MID manual, list of contents
As previously mentioned, there is a MID manual for each control unit, this example shows the manual for MID 128, i.e. the engine control unit found under group 28 in Impact, or alternatively the service subscription. All MID manuals have the same layout. The first page of the manual contains the list of contents, with page references to all fault codes that can occur. One should be aware that this manual covers all of Volvo Buses newer electronically controlled engines, such as DH12C/D, GH10C D9A and D7C. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Global Training GT2300113eng
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G r o u p 2 8 M I D 12 8 E n g in e c o n tr o l u n it ( E EC U )
M u l ti p le x e d e le G e ne c tr i r al c a l s ys te m
V o lv o B e le c tr i u s h a s i n tr o s u b s c a l s y s te d u ce y st em s m c s is d a n i n t e a n d f on g ra g o t e T he u n ct i ti n m o n s i f c o n tr o l d m u lt ip u l le x A- bu n t h e u ex e d s h lt ip b u s. n it s t h a t d e d e le c tr i f u n ct a n d le M I D ef in c 2 34 s t h e e t h a l s y io n s B IC s t d r e a D - bu e f u e m h s f o r m n d t h e C iv e li n a s f o M I D 14 4 - bu n c ti o u r d a s t i n g a V EC U t a l in l in T h e k b h e c h a n s, t h e c J 17 0 e t we M I D e n s s is f u B - bu s t ks : T h e 8 / J1 5 8 12 8 c o n tr o n tr o l u n i 7 he b o E EC t h e C n ct io U o l l in t s n o s d n y b M I D w k C on u t i h e A s a n d th t h J 19 3 t r o 2 4 9 M I D - e B BM A 13 0 s c - Bu t h e B s n al 9 a n d a bu T a n d d l s ig E C o U m b r e s lo u m ia g n o s a s u n ic a . M si s s i s e nt o w e r i n fo I D 1 D - B u o r m a te s n t g n al s AB S 3 6 r a / EB ti o S ve M I D a r e s h e f a st l in 2 2 k J 1 f a st k, w n l in AI C 1 e nt o M I D 7 15 0 8 . h il e n t h e 0 M I D E C 18 i S n fo r m J 19 3 s lo C EC w E ng M 8 l in 9 1 i n a t io - B k. n e M I D c 2 T h e LC M 16 on t r o e c o n tr n gi n e e le l B -B M I D u ct ro s o 2 n ic u ni t ( R E C 2 2 u n it c ls e n g in U E c o n a e r e la l u n E CU d r e t ro c o m i r r ie s o u t te ) n C la y s i t ( EE re U t h e c g d ir e ct ly d if f e a n d s e n s ) c h e ck s o m n t f u n c ti o o rs . c o nt r n tr o l u n it f ro a n t n h s e u s o l u n a s e i n d a n so n g i n T h e c o n d r s M u lt i I / O - it w ay , A fo r m t ro pl e t h x e u g ls o s ig t h e e s t h ro a d e t a ti o n l h t h e n a ls o b a r e c o a va il n e le c t r i n c a bl e g in d t n a a a c l e i li n n e d s ys t e c te i nf o i s a v k m r m o n tr o l u n ta h e d t o a il a bl e it ( E E s. I n a c f r o m t n o f o r a ti o o th o r re C U ) e r n t he t s h p s e T h e o e n d s c o o t h e r e g s o n d in o c o nt r mm f u n c t n g in e o l u n n d a t a l i n me o f i t io n s c o n t ro l u n i k t s s . s e tt in s s o t h s i t ( EE a s g a u ch a t i t CU e n d f u e l i n j n g in e p r e ) c o n t ro ls a T h e e e c ti o h e a t i n n n d n g . g , s lo e c i n t e g in w i d c h ec k s o n tr o ra l e s p l u n it e le ct r i t e d m u lt ip e e d ( E EC c l a e x e le U f o u n d l s y st e ) c c tr ic a o n st i m i n ” t l s y s T o s e V o lv o p a g e 3 te m u t e s p a b e “ E n g s p e c if i c u s e s i rr e f o r m o r e ; s e e “ M r t o f t h e s in e c a t io i n p f e o n s c t i r m a t u lt i pl ex e o n tr o n , w d l u n it o f t h e e n ve o f o th e r io , E E C g in i s i h ic h U” p a e c o n t r e qu e n o l u n pm g e 4 i t, r e f t. er t o
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G e n e r a l
M I D 2 M AS T 10 ER I D
R S 2 3 2 P C
I / O - B T 30 16 118
MID manual, system description, specifications
The manual contains a general description of the electrical syst em, communication link functions, etc. There is also a description of the engine control unit’s (EECU) funct ion. Page four contains the engine control unit (EECU) specificati ons. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Global Training GT2300113eng
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G ro up 2 8
M I D 12 8 E ng i ne c o n tr o l u n i t ( EE CU )
S pe c ia l t o ol s
T o ol s
F o r i n fo r m g r ou n o p n 0 8 a t io o rd . er in g s pe c i a l t oo ls , p l ea s e r e fe r t o t he s p e c ia l t o o l s i n fo r ma ti o n,
T oo ls
86 M ea s u r 9 99 e me n t 9 9 b ox 6 2 -p in
9 81 2 5 M u lt i 19 m et e r
x
9 9 9 34 Ad a p 85 te r c a bl e
9 99 8 56 7 Ad ap t e r c a bl e
9 99 85 0 5 Ad ap te r c a bl e
8
MID manual, tools
Even the adapter cables used for manual measurement (with the use of the breakout box and multimeter) of the control unit and it’s wiring, sensors and functions are stated in the manual. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Global Training GT2300113eng
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G ro u p 2 8 M ID 1 2 8 E n
D e s ig n
g i ne c o nt ro l u ni t ( EE C U )
D es i g n an d F un c t io n
T he c on r p i n h av e d ne ct o s o n t h i ff e r en t e le e e ng i n u se d c f o r e c o nt r l p r e t he d i ff tr i ca r t ie er en s. T h ol u ni t ( EE t s i g op C U nal t yp H DI e s a r e a b br ev i at i ) on s e d e sc H i gh r i be D i g d b e l LD I i ta l I np u ow . t Lo w D i gi ta G DI l I np ut G e ne r al D ig i t al I np u s el ec t a b le t ( HD H DO I / LD ) I, H i gh D ig it a LD O l O u tp u t Lo w D ig it a H TD l O u t I pu t H i g h D ig it al I n LT DI p u t T r u e Lo w D ig it al I n H LD I p ut T r u e H i gh L o w AI D i gi ta l I np u t Anal o g ue I np AO u t Anal o g ue O u R ES tp u t R e si st a nc e T he s ig nal t y p es H D l o gi cs an I, L D I, H DO h av e t d s tr uc t u r e he re c o n a nd L D O h a r e d i f i n t he t h at t h fo v e d i ff e t r ol u ni fe r en e l i mi ts t p ro re nt pe s i gn r ti es t. T he f o r t he p r og r am al s d i ff e ; s ee m a r b t e a l n e b l e. N t s i g na t he d i ff a n d c o an t he l c ha e t p te re r e i n f ul ly i n r en r is t i c d i f r ac te d iv a s . S i gn al t y fo r s l ig ht l y b s ar e pe s A O fe l p ro no t b e i du g r et w , A I a n e c ov e e b n re d i n am ma d P WM pe m or e d l e p ro e ta i l h er r ti es and w il h av e Li mi ts , l t h er e e. % o f U fo r e b at U > 7 5 % H DI 2 5%
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