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Diagnostic Manual, Diesel Engines, Volume 1.1

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LOCATION:    3.1 In-line Fuel Injection (IFI)    >   23 Electrical Test Program - Test


Electrical Test Program - Test

Test scope
Test connection
Test condition Nominal value Possible cause/Remedy
1.0 IFI control module (N3/7)
Voltage supply
Circuit 87 unfused



19
18
N3/7





37
55
Ignition: ON
11 - 14 V Relay module (K40) (Figure 1),
Wiring,
1.1
1.1   Ground, component compartment - right (W16/6)
N3/7

18

19





X12/3

X12/3

Ignition: OFF 11 - 14 V Ground W16/6,
1.2
1.2   Holding relay activation
Terminal HRL

N3/7

26





X12/3

Ignition: ON or engine at CTP (idle)

Engine : Shut off 		11 - 14 V


11 - 14 V for approx. 4 sec. then < 1 V
Relay module (K40),
IFI control module (N3/7),
Wiring.
2.0 Circuit 15U


18
N3/7



47


Ignition: ON


11 - 14 V 		Check voltage supply,
Wiring.
3.0 Relay module (K40)
Voltage supply
Model 210 up to 02/67
Plug
B
5
K40

Plug
B
4
Ignition: OFF

Disconnect plug B

11 - 14 V 		Check voltage supply,
Wiring,
Output ground, component compartment - right (W15/1),
Relay module (K40),
4.0 ECT sensor (B11/4)
Voltage


4
N3/7



23
Ignition: ON oC V
20 3.7
30 3.4
40 3.0
50 2.6
60 2.1
70 1.8
80 1.5
90 1.2
± 10%
B11/4 (Figure 2),
Wiring,
IFI control module (N3/7)
4.1
4.1   Resistance


4
N3/7



23
Ignition: OFF
Disconnect plug on IFI control module (N3/7) 		oC
20 2500
30 1700
40 1170
50 830
60 600
70 435
80 325
90 245
± 10%
B11/4 (Figure 2)
Wiring,
4.2
4.2   B11/4

1
B11/4

2
Ignition: OFF
Disconnect plug on
ECT sensor (B11/4) 		Nominal values see 4.1 B11/4 (Figure 2).
5.0
IAT sensor (B17)
Voltage


4
N3/7



40
Engine: At CTP
oC V
20 3.3
30 2.9
40 2.5
±5%
B17 (Figure 3),
Wiring,
IFI control module (N3/7),
5.1
5.1   Resistance


4
N3/7



40
Ignition: OFF
Remove plug on IFI control module (N3/7) 		oC
20 6060
30 3900
40 2600
±5%
B17 (Figure 3),
Wiring,
5.2
5.2   B17

2
B17

1
Ignition: OFF
Remove plug on
sensor B17 (Figure 3)
Nominal values see 5.1 B17.
6.0 Pressure sensor (B28)

Note for connection:
Connect pressure tester with Y-fitting to pressure sensor


6
N3/7



22


Engine: At CTP

Slowly increase engine speed to 2500 rpm


> 2.5 V

Voltage: Drops
Vacuum: Rises


6.1

Pressure lines.
6.1   B28



6
N3/7




45


Ignition: ON


4.8 - 5.2 V 		B28 (Figure 4),
Wiring,
IFI control module (N3/7).
7.0
CKP sensor (L5/6)


28




28
N3/7 2)




N3/7 1)



20




20


Engine: At CTP




Engine: At CTP




Cranking rpm: > 200 rpm


Signal see
Figure 5



> 0.8 V~ increasing rpm
= increasing
voltage

> 0.3 V~ 		Installation position of sensor,
Dirt on sensor (metal chips),
Segments on flywheel,
7.1
7.1   Resistance of sensor L5/6


28
N3/7



20
Ignition: OFF 680 - 1300 Connector L5/6x1 (Figure 6),
Wiring,


8.0

Fuel quantity actuator
(Y23/1)
Adjustment solenoid


36
54
N3/7




37
37


Ignition: ON

> 4.0 V max. for 30 seconds
8.1
8.1   Resistance


36
54
N3/7




37
37
Ignition: OFF
Remove connector on IFI control module (N3/7)

1.2 ± 0.2
1.2 ± 0.2
Connector (Y23/1x1) (Figure 7),
Y23/1,
N3/7,
Wiring.
9.0

Fuel rack position sensor
(Y23/1l1)


19
N3/7



9


Ignition: ON


2.2 - 2.7 V 		Connector (Y23/1x1) (Figure 7),
9.1
9.1    


19
N3/7



10


Ignition: ON

2.2 - 2.7 V 		N3/7,
Wiring,
9.2
9.2   Resistance


46
10
N3/7




9
9
Ignition: OFF
Remove connector on IFI control module (N3/7)

23 ±5%
45 ±5%
Y23/1,
Wiring.
10.0
IFI accelerator pedal
position sensor (R25/2)


6

6
N3/7





29

39


Ignition: ON

CTP position:
Full load position:


> 4.5 V

<0.5 V
>4.3 V 		R25/2 (Figure 8)
Wiring,
IFI control module (N3/7),
W16/6,
10.1
10.1   CTP contact switch (R25/2s1)


18


15
N3/7







15


24
Ignition: ON

CTP position:
Full load position:

CTP position:
Full load position:


> 4.5 V
<0.5 V

<0.5 V
> 4.5 V
R25/2 (Figure 8)
Wiring,
IFI control module (N3/7),
W16/6.
11.0 Starter lock-out/backup
lamp switch (S16/1)


18
N3/7



12
Ignition: ON
AT range: P/N

Engine: Start 4) R

0 V

11 - 14 V
S16/1,
Wiring.
12.0 Stop lamp switch (S9/1)
Signal (S9/1s1)


18
N3/7



31
Ignition: ON
Brake pedal:
not depressed

depressed


< 1 V

11 - 14 V 		Wiring,
Stop lamp switch (S9/1),
(Figure 9),
W16/6,
12.1
12.1   Voltage supply
Circuit 87E

S9/1x1

2
Remove connector S9/1x1

Ignition: ON

11 - 14 V 		Wiring,
Voltage supply,
12.2
12.2   Stop lamp switch (S9/1)

1
S9/1x1

2
Ignition: OFF
Remove connector S9/1x1

Brake pedal:
not depressed

depressed




> 20 k

< 1 		Stop lamp switch (S9/1)
(Figure 9).
13.0 Stop lamp switch (S9/1)
Signal (S9/1s2)


18
N3/7



27
Ignition: ON

Brake pedal:
not depressed

depressed


11 - 14 V

< 1 V
Wiring,
Stop lamp switch (S9/1)
(Figure 9),
13.1
13.1   Voltage supply
Circuit 87E

S9/1x2

2
Remove connector S9/1x2

Ignition: ON

11 - 14 V
Wiring,
Voltage supply,
13.2
13.2   Stop lamp switch

1
S9/1x2

2
Ignition: OFF
Remove connector S9/1x2

Brake pedal:
not depressed

depressed




< 1

> 20 k 		Stop lamp switch (S9/1).
14.0 ETS - slip recognition signal


18
N3/7



7

Ignition: ON

Engine: at CTP (idle)
< 1 V

11 - 14 V 		ETS/SPS control module (N47-2),
Wiring.
15.0 VSS from ABS control module (N30) or ETS/SPS control module (N47-2)


4




4
N3/7 2)



N3/7 1)



25




25
Ignition: ON
Move vehicle approx. 3 ft.
(1 m)




Signal see
Figure 10



> 2.0 V~ 		Check N30, N47-2 see DM, Chassis and Drivetrain, Volume 2, Section 6.3,
Wiring.
16.0 CC switch (S40)

SP Resume




V Decelerate/set



B Accelerate/set



A Off





Safety contact


18




18





18



18






18
N3/7




N3/7



N3/7



N3/7





N3/7



42




38





8



44






30
Ignition: ON
Switch S40s1 not actuated

Position: RESUME


S40s2
Position: DECELERATE


S40s3
Position: ACCELERATE



Switch S40s4 not actuated

Position: OFF


Switch S40s5not actuated

Position: DECELERATE, ACCELERATE, RESUME, OFF


< 1 V

11 - 14 V




11 - 14 V




11 - 14 V



11 - 14 V


< 1 V


< 1 V


11 - 14 V
Wiring,
CC switch (S40).
17.0 CHECK ENGINE MIL
(A1e26)


17
N3/7



37
Ignition: ON

Engine: Start 		11 - 14 V

Temporarily:
11 - 14 V,
CHECK
ENGINE MIL
(A1e26) lights
briefly for
approx. 1 sec. 5)
CHECK ENGINE MIL (A1e26)
(Figure 16 + 17),
IFI control module (N3/7).


18.0   Non-USA vehicles only.




  		   
19.0 Modulating pressure
switchover valve (Y3/4)
Voltage


49
N3/7



37

Engine: At CTP 6)

CC in operation
> 25 mph (40 km/h)
< 0.5 V
>350 mbar

11 - 14 V
< 35 mbar
IFI control module (N3/7),
Vacuum lines,
Vacuum supply,
Wiring,
Vacuum control valve,
Throttle linkage,
19.1
19.1   Current draw

18


49

Ignition: ON

0.40 A 		Switchover valve (Y3/4)
(Figure 12).
20.0   Non-USA vehicles only.




  		   
21.0 Upshift delay switchover
valve (Y3/5)


34
N3/7



37
Engine: At CTP 6)


CC in operation
> 25 mph (40 km/h)
< 0.5 V
< 35 mbar

11 - 14 V
> 350 mbar 		IFI control module (N3/7),
Vacuum lines,
Vacuum supply,
Wiring,
21.1
21.1   Current draw

18


34

Ignition: ON
0.40 A
Upshift delay switchover
valve (Y3/5) (Figure 12).
1) Test with multimeter only if oscilloscope is not available.
2) Test with oscilloscope. This test can be performed at idle speed with the Bear DACE engine analyzer. Set time axis to 25 milliseconds.
4) Engine does not start
5) With malfunctions which prevent starting of engine or severely influence engine running, the voltage is continuously present or the CHECK ENGINE MIL lights continuously until the failure is eliminated.
6) Briefly apply WOT, vacuum and voltage decrease. The test values are reference values.

Test scope
Test connection
Test condition Nominal value Possible cause/Remedy
22.0
Electrohydraulic shut-off
actuator (Y1/1)
Activation


18
N3/7



43
Engine: At CTP 11 - 14 V IFI control module (N3/7),
Wiring,
22.1
22.1   Current draw
N3/7

43



X12/3

Ignition: OFF
Control module removed


1.4 A 4) 		22.2
22.2   Resistance

2
Y1/1


3
Ignition: OFF
Remove plug from IFI control module (N3/7)


8.1 ± 0.5 		Y1/1

23.0
Fuel temperature sensor (Y1/1b1)


28
N3/7



3
Engine: At CTP oC V
20 3.9
30 3.5
40 3.0
50 2.6
23.1
23.1   Resistance


4
N3/7



3
Ignition: OFF
Remove connector on IFI control module (N3/7) 		oC
20 2500
30 1700
40 1170
50 830
23.2
23.2   Y1/1b1

1
Y1/1b1

4
Ignition: OFF
Remove connector on electrohydraulic shut-off actuator (Y1/1) (Figure 14)
Nominal values see 23.1 Electrohydraulic shut-off actuator (Y1/1).
24.0   IFI control module (N3/7)
Signal from automatic A/C


18
N3/7



33
Engine: At CTP

Engine: Briefly apply WOT 		11 - 14 V

< 1 V 		A/C pushbutton control
module (N22),
Wiring.
25.0 CAN data bus


41
N3/7



5
Ignition: OFF 59 - 61 Data line,
IFI control module (N3/7).
25.1
25.1   CAN element in RCL control module (N54)
Resistance


41
N3/7



5
Ignition: OFF
Remove connector on IFI control module (N3/7)
118 - 122 RCL control module (N54),
Data line,
25.2
25.2   Data bus
N3/7
41

5



N54
H

L
Ignition: OFF

Remove connectors on IFI control module (N3/7) and RCL control module (N54)
< 1 Wiring.
26.0
Resonance intake line
switchover valve (Y22/6)
Voltage


51
N3/7



37
Engine: at CTP (idle)
660 rpm ± 10

1500 rpm ± 10

11 - 14 V

< 1 V 		IFI control module (N3/7),
Wiring,
Resonance intake line switchover valve (Y22/7) (Figure 14),
26.1
26.1   Current draw

18


11

Ignition: ON

0.4 A 		Resonance intake line switchover valve (Y22/7) (Figure 14).
27.0
Resonance intake manifold
switchover valve (Y22/7)
Voltage


11
N3/7



37
Engine: at CTP (idle)
660 rpm ± 10

3700 rpm ± 10

11 - 14 V

< 1 V 		IFI control module (N3/7),
Wiring,
Resonance intake manifold witchover valve (Y22/6)
(Figure 14),
27.1
27.1   Current draw

18


51

Ignition: ON

0.4 A 		Resonance intake manifold witchover valve (Y22/6)
(Figure 14).
28.0   Signal for tachometer
TD signal


18




18
N3/7 2)



N3/7 1)



14




14


Engine: at CTP (idle)



Engine: at CTP (idle)
Signal see Figure 15



> 0.8 V~
Increasing rpm = increasing voltage
IFI control module (N3/7).

29.0   Non-USA vehicles only.



     
30.0
EGR lifting sender (B28/3)


28
N3/7



21
Engine: at CTP (idle) 7)

Accelerate briefly, then
Engine: at CTP (idle) 		< 1.5 V
< 100 mbar

> 1.5 V
> 150 mbar 		30.1
30.1   EGR valve leakage

Remove vacuum line and connect pressure tester



Ignition: OFF

Apply 400 mbar vacuum to EGR valve.
Pull off vacuum line.


EGR valve closes audibly 		EGR valve (see 31 ,
Figure 1)

31.0 EGR valve vacuum
transducer (Y31/1)
Vacuum at outlet "OUT" of vacuum transducer


35
N3/7



37
Engine: at CTP (idle) 7)
660 ± 10 rpm


2000 ± 100 rpm


Briefly apply WOT 6)
< 1.0 V
< 150 mbar

> 2 V
> 200 mbar

< 1.0 V
< 150 mbar
IFI control module (N3/7),
Vacuum transducer (Y31/1),
Vacuum lines,
Wiring,
Vent filter dirty.
32.0
Pressure control flap
vacuum transducer (Y31/2)
Vacuum at outlet "OUT" of vacuum transducer


53
N3/7



37
Engine: at CTP (idle)
660 ± 10 rpm 7)


Accelerate briefly, then
Engine: at CTP (idle)
for approx. 50 seconds

< 1.5 V
< 150 mbar

> 2.5 V
>200 mbar
IFI control module (N3/7),
Vacuum transducer (Y31/2),
Vacuum lines,
Wiring,
Vent filter dirty.
1) Test with multimeter only if oscilloscope is not available.
2) Test with oscilloscope. This test can be performed at idle speed with the Bear DACE engine analyzer. Set time axis to 25 milliseconds.
4) Electrohydraulic sut-off actuator clicks audibly.
6) Briefly apply WOT, vacuum and voltage decrease. The test values are reference values.
7) If EGR was recirculated previously, a waiting time of 50 seconds must be observed, after that, the values can be checked.

 
   



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