Nissan Frontier D40. Manual - part 397

P0603 ECM POWER SUPPLY

EC-279

< COMPONENT DIAGNOSIS >

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P0603 ECM POWER SUPPLY

Component Description

INFOID:0000000005273287

Battery voltage is supplied to the ECM even when the ignition switch
is turned OFF for the ECM memory function of the DTC memory, the
air-fuel ratio feedback compensation value memory, the Idle Air Vol-
ume Learning value memory, etc.

On Board Diagnosis Logic

INFOID:0000000005273288

DTC Confirmation Procedure

INFOID:0000000005273289

NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
1.

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next step.

a.

Turn ignition switch OFF and wait at least 10 seconds.

b.

Turn ignition switch ON.

c.

Turn ignition switch OFF and wait at least 10 seconds.

2.

Turn ignition switch ON, wait at least 10 seconds.

3.

Turn ignition switch OFF, wait at least 5 minutes.

4.

Turn ignition switch ON, wait at least 10 seconds.

5.

Repeat steps 2 to 3 for 5 times.

6.

Check 1st trip DTC.

7.

If 1st trip DTC is detected, go to 

EC-279, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000005273290

1.

CHECK ECM POWER SUPPLY

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

PBIB1164E

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0603
0603

ECM power supply circuit

ECM back up RAM system does not function 
properly.

• Harness or connectors

[ECM power supply (back up) circuit is 
open or shorted.]

• ECM

EC-280

< COMPONENT DIAGNOSIS >

[QR25DE]

P0603 ECM POWER SUPPLY

3.

Check voltage between ECM terminal 121 and ground with
CONSULT-III or tester.

OK or NG

OK

>> GO TO 3.

NG

>> GO TO 2.

2.

DETECT MALFUNCTIONING PART

Check the following.
• 20A fuse (No.53)
• IPDM E/R harness connector E121
• Harness for open or short between ECM and battery

>> Repair or replace harness or connectors.

3.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-46, "Intermittent Incident"

.

OK or NG

OK

>> GO TO 4.

NG

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

4.

PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT-III

1.

Turn ignition switch ON.

2.

Select “SELF DIAG RESULTS” mode with CONSULT-III.

3.

Touch “ERASE”.

4.

Perform DTC Confirmation Procedure.
See 

EC-279, "DTC Confirmation Procedure"

.

5.

Is the 1st trip DTC P0603 displayed again?

With GST

1.

Turn ignition switch ON.

2.

Select Service $04 with GST.

3.

Perform “DTC Confirmation Procedure”.
See 

EC-279, "DTC Confirmation Procedure"

.

4.

Is the 1st trip DTC P0603 displayed again?

Yes or No

Yes

>> GO TO 5.

No

>> INSPECTION END

5.

REPLACE ECM

1.

Replace ECM.

2.

Perform initialization of NVIS (NATS) system and registration of all NVIS (NATS) ignition key IDs. Refer to

SEC-7, "ECM RE-COMMUNICATING FUNCTION : Special Repair Requirement"

.

3.

Perform 

EC-24, "VIN Registration"

.

4.

Perform 

EC-24, "Accelerator Pedal Released Position Learning"

.

5.

Perform 

EC-24, "Throttle Valve Closed Position Learning"

.

6.

Perform 

EC-24, "Idle Air Volume Learning"

.

>> INSPECTION END

Voltage: Battery voltage

MBIB0026E

P0605 ECM

EC-281

< COMPONENT DIAGNOSIS >

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P0605 ECM

Component Description

INFOID:0000000005273291

The ECM consists of a microcomputer and connectors for signal
input and output and for power supply. The ECM controls the engine.

On Board Diagnosis Logic

INFOID:0000000005273292

This self-diagnosis has one or two trip detection logic.

FAIL-SAFE MODE

ECM enters fail-safe mode when malfunction A is detected.

DTC Confirmation Procedure

INFOID:0000000005273293

Perform PROCEDURE FOR MALFUNCTION A first. If the 1st trip DTC cannot be confirmed, perform
PROCEDURE FOR MALFUNCTION B. If there is no malfunction on PROCEDURE FOR MALFUNCTION
B, perform PROCEDURE FOR MALFUNCTION C.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.

PROCEDURE FOR MALFUNCTION A

 With CONSULT-III

1.

Turn ignition switch ON.

2.

Check 1st trip DTC.

3.

If 1st trip DTC is detected, go to 

EC-282, "Diagnosis Procedure"

.

 With GST

Follow the procedure “With CONSULT-III” above.

PROCEDURE FOR MALFUNCTION B

 With CONSULT-III

1.

Turn ignition switch ON and wait at least 1 second.

2.

Turn ignition switch OFF, wait at least 10 seconds and then turn it ON.

3.

Check 1st trip DTC.

4.

If 1st trip DTC is detected, go to 

EC-282, "Diagnosis Procedure"

.

PBIB1164E

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0605
0605

Engine control module

A)

ECM calculation function is malfunctioning.

• ECM

B)

ECM EEP-ROM system is malfunctioning.

C)

ECM self shut-off function is malfunctioning.

Detected items

Engine operation condition in fail-safe mode

Malfunction A

• ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 

degrees) by the return spring.

• ECM deactivates ASCD operation.

EC-282

< COMPONENT DIAGNOSIS >

[QR25DE]

P0605 ECM

 With GST

Follow the procedure “With CONSULT-III” above.

PROCEDURE FOR MALFUNCTION C

 With CONSULT-III

1.

Turn ignition switch ON and wait at least 1 second.

2.

Turn ignition switch OFF, wait at least 10 seconds and then turn it ON.

3.

Repeat step 2 for 32 times.

4.

Check 1st trip DTC.

5.

If 1st trip DTC is detected, go to 

EC-282, "Diagnosis Procedure"

.

 With GST

Follow the procedure “With CONSULT-III” above.

Diagnosis Procedure

INFOID:0000000005273294

1.

INSPECTION START

With CONSULT-III

1.

Turn ignition switch ON.

2.

Select “SELF DIAG RESULTS” mode with CONSULT-III.

3.

Touch “ERASE”.

4.

Perform DTC Confirmation Procedure.
See 

EC-281, "DTC Confirmation Procedure"

.

5.

Is the 1st trip DTC P0605 displayed again?

With GST

1.

Turn ignition switch ON.

2.

Select Service $04 with GST.

3.

Perform DTC Confirmation Procedure.
See 

EC-281, "DTC Confirmation Procedure"

.

4.

Is the 1st trip DTC P0605 displayed again?

Yes or No

Yes

>> GO TO 2.

No

>> INSPECTION END

2.

REPLACE ECM

1.

Replace ECM.

2.

Perform initialization of NVIS (NATS) system and registration of all NVIS (NATS) ignition key IDs. Refer to

SEC-7, "ECM RE-COMMUNICATING FUNCTION : Special Repair Requirement"

.

3.

Perform 

EC-24, "VIN Registration"

.

4.

Perform 

EC-24, "Accelerator Pedal Released Position Learning"

.

5.

Perform 

EC-24, "Throttle Valve Closed Position Learning"

.

6.

Perform 

EC-24, "Idle Air Volume Learning"

.

>> INSPECTION END