Infiniti QX4 (R50). Manual — part 169

MEC941C

GI

MA

EM

LC

FE

AT

TF

PD

AX

SU

BR

ST

RS

BT

HA

SC

EL

IDX

TROUBLE DIAGNOSIS FOR POWER SUPPLY

Main Power Supply and Ground Circuit (Cont’d)

EC-143

DIAGNOSTIC PROCEDURE

NBEC0049

1

INSPECTION START

Start engine.
Is engine running?

Yes or No

Yes

©

GO TO 9.

No

©

GO TO 2.

2

CHECK ECM POWER SUPPLY CIRCUIT-I

1. Turn ignition switch “OFF” and then “ON”.
2. Check voltage between ECM terminal 43 and ground with CONSULT-II or tester.

SEF291X

OK or NG

OK

©

GO TO 4.

NG

©

GO TO 3.

3

DETECT MALFUNCTIONING PART

Check the following.

I

10A fuses

I

Harness connectors M33, F22

I

Harness for open or short between ECM and ignition switch

©

Repair harness or connectors.

4

CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I

1. Turn ignition switch “OFF”.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminals 48, 57, 106, 108 and engine ground.

Refer to WIRING DIAGRAM.

Continuity should exist.

4. Also check harness for short to ground and short to power.

OK or NG

OK

©

GO TO 5.

NG

©

Repair open circuit or short to ground or short to power in harness or connectors.

TROUBLE DIAGNOSIS FOR POWER SUPPLY

Main Power Supply and Ground Circuit (Cont’d)

EC-144

5

CHECK POWER SUPPLY-II

1. Disconnect ECM relay.

SEF681UB

2. Check voltage between ECM relay terminals 1, 5 and ground with CONSULT-II or tester.

SEF956Y

OK or NG

OK

©

GO TO 7.

NG

©

GO TO 6.

6

DETECT MALFUNCTIONING PART

Check the following.

I

7.5A and 10A fuses

I

Harness for open or short between ECM relay and battery

©

Repair open circuit or short to ground or short to power in harness or connectors.

7

CHECK OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Check harness continuity between ECM terminal 26 and ECM relay terminal 2.

Continuity should exist.

2. Also check harness for short to ground and short to power.

OK or NG

OK

©

Go to “DTC P1320 IGNITION SIGNAL”, EC-499.

NG

©

GO TO 8.

8

DETECT MALFUNCTIONING PART

Check the following.

I

Harness connectors E1, M1 and M32, F23

I

Harness for open or short between ECM relay and ECM

©

Repair open circuit or short to ground or short to power in harness or connectors.

GI

MA

EM

LC

FE

AT

TF

PD

AX

SU

BR

ST

RS

BT

HA

SC

EL

IDX

TROUBLE DIAGNOSIS FOR POWER SUPPLY

Main Power Supply and Ground Circuit (Cont’d)

EC-145

9

CHECK ECM POWER SUPPLY CIRCUIT-II

1. Stop engine.
2. Check voltage between ECM terminal 67 and ground with CONSULT-II or tester.

SEF293X

OK or NG

OK

©

GO TO 11.

NG

©

GO TO 10.

10

DETECT MALFUNCTIONING PART

Check the following.

I

Harness connectors E1, M1 and M32, F23

I

Harness for open or short between ECM and fuse

©

Repair harness or connectors.

11

CHECK ECM POWER SUPPLY CIRCUIT-III

1. Turn ignition switch “ON” and then “OFF”.
2. Check voltage between ECM terminals 110, 112 and ground with CONSULT-II or tester.

SEF294X

OK or NG

OK

©

GO TO 17.

NG (Battery voltage
does not exist.)

©

GO TO 12.

NG (Battery voltage
exists for more than a
few seconds.)

©

GO TO 14.

TROUBLE DIAGNOSIS FOR POWER SUPPLY

Main Power Supply and Ground Circuit (Cont’d)

EC-146