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Diagnostic Manual, Engines, Volume 3

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LOCATION:    8.5 Diagnostic Module (DM)   >   23 Electrical Test Program - Test


Electrical Test Program - Test

Test scope Test connection Test condition Nominal value Possible cause/Remedy
1.0 P 1 7 5 0 Diagnostic module (OBD II , N59/1)
Voltage supply
Circuit 30


2
(1.2)
N59/1



4
(1.4)


Ignition: ON


11 - 14 V
Wiring,
1.1 ,
Model 129
Base module (N161/1)
Model 202
Fuse (F1-32).
1.1   Ground wire N59/1

2
(1.2)


X11/4

3


Ignition: ON


11 - 14 V
Wiring,
Model 129
Ground (module box bracket, W27, Figure 1)
Model 202
Ground (component compartment, W16/4, Figure 2)
2.0   Diagnostic module (OBD II , N59/1)
Voltage supply
Circuit 87E


15
(1.15)
N59/1



3
(1.3)


Ignition: ON


11 - 14 V
Wiring,
2.1 ,
Model 129
Base module (N161/1)
Model 202
Overvoltage protection relay module (K1/2)
2.1   Ground wire to engine control module

15
(1.15)
N59/1



4
(1.4)


Ignition: ON


11 - 14 V
Wiring
3.0   "CHECK ENGINE" MIL (A1e26)
Control


9
(1.9)
N59/1



3
(1.3)


Ignition: ON


11 - 14 V
Diagnostic module (OBD II, N59/1)
4.0 P 0 1 3 2
P 0 1 3 4
P 0 1 3 1
P 1 1 3 1
P 0 1 3 3
O2S 1 (before TWC) (G3/2)
Signal


2
(1.2)
N59/1



14
(1.14)
Engine: at Idle
and at operating temperature (80 °C). Run engine at idle for at least 2 minutes.
oscillates between -0.2V and +1.0 V, by more than
0.3 V.
Wiring,
G3/2.
5.0 P 0 1 3 8
P 1 1 3 7
P 1 1 3 8
O2S 2 (after TWC) (G3/1)
Signal


2
(1.2)
N59/1



11
(1.11)
Start engine at engine coolant temperature
> 80°C.


Maintain an engine speed of 2000 - 3000 rpm for approx. 3 minutes until O2S 2 (after TWC) heater is switched on (see HHT).

Accelerate briefly



450 mV constant

Voltage changes







Voltage changes by
> 100 mV
Wiring,
G3/1.
6.0 P 1 3 3 5 Engine speed signal
TNA


2
(1.2)




2
(1.2)
N59/1 1)




N59/1 2)



19
(1.19)




19
(1.19)
Engine: at Idle

Signal (Fig. 3)




5.0 - 7.5 V
Wiring,
Engine control module (N3/4).
7.0 P 1 3 4 0 CMP sensor (L5/1)
Output signal


2
(1.2)



2
(1.2)
N59/1 1)




N59/1 2)



20
(1.20)



20
(1.20)
Engine: at Idle

Signal (Fig. 4)




9.5 - 11.0 V
(voltage jumps)
Wiring,
CMP sensor (L5/1),
Engine control module (N3/4).
8.0 P 1 4 4 3 Purge flow switchover
valve (Y27/6)
Current draw


2
(1.2)
N59/1



12
(1.12)


Ignition: ON


0.4 - 0.6 A
Wiring,
Y27/6.
9.0 P 0 4 4 1 Purge flow system
Logic chain


2
(1.2)
N59/1



12
(1.12)
Connect vacuum tester to switchover valve (Y27/6) (Figure 5)
Engine: Start and bring to operating temperature
(80 °C).
Engine speed approximately 2500 rpm
Purge switchover valve (Y58/1) noticeably cycles.
Vacuum tester needle oscillates by approx. 5 mbar vacuum with cycle frequency of the purge control valve (Y58/1)
Regeneration line,
Purge control valve (Y58/1),
Y27/6.
10.0 P 1 4 4 4 Purge flow switchover
valve (Y27/6)
Logic chain vacuum switchover


2
(1.2)
N59/1



12
(1.12)
Connect vacuum tester to switchover valve (Y27/6).
Disconnect 2-pole connector from purge control valve (Y58/1).
Engine: at Idle


Remove bridge from socket box tester





approx. 0 mbar vacuum

> 500 mbar vacuum
Vacuum line,
Y27/6).
11.0 P 0 1 0 5 DM pressure sensor (B5/2)
Voltage


1
(1.1)
N59/1



18
(1.18)
Connect vacuum tester to pressure sensor (B5/2) using Y-fitting (Figure 5).
Ignition: ON

Engine: at Idle



> 3.5 V

< 2 V and vacuum increase to
> 500 mbar
Vacuum line,
Wiring,
11.1 ,
B5/2.
11.1   DM pressure sensor (B5/2)
Voltage supply


1
(1.1)
N59/1



22
(1.22)


Ignition: ON


4.7 - 5.3 V
Diagnostic module (OBD II, N59/1)
12.0   Diagnostic module coding

Model 129








Model 202 (Engine 104 only)


7
(1.7)



8
(1.8)



7
(1.7)
N59/1








N59/1




3
(1.3)



3
(1.3)



3
(1.3)
Ignition: ON

11 - 14 V Wiring.
13.0 P 0 6 0 0 CAN databus
L
N59/1

H
Ignition: OFF
Disconnect test cable or diagnostic module.
Test with ohmmeter directly on both connections of diagnostic module connector
(Figure 6).
55 - 65 Data bus,
13.1 ,
Diagnostic module (OBD II, N59/1).
13.1   CAN segment in engine control module (N3/4)
L
N3/4

H
Model 129
Remove control module (N3/4)



Model 202
Disconnect connector 1 from control module (N3/4) and test with ohmmeter directly on control module (Figure 7 and 8)
Models 129, 202
(with Engine 104)
115 - 125

Model 202 (with Engine 111)
55 - 65
Engine control module (N3/4),
13.2.
13.2   On engine 104 to end of Model Year 1995
CAN segement in EA/CC/ISC control module (N4/1) or CC/ISC control module (N4/3)


On engine 104/111 as of Model Year 1996
CAN segement in RCL control module (N54)

20
(1.20)


44
(1.44)


L
N4/1



N4/3



N54

21
(1.21)


45
(1.45)


H
Disconnect control module (N4/1, N4/3 or N54) and test with ohmmeter directly on control module (Figure 9 - 13). 115 - 125 EA/CC/ISC control module (N4/1), CC/ISC control module (N4/3) or RCL control module (N54).
1) Test with oscilloscope.
2) Test with digital multimeter only if oscilloscope is not available.