Nissan Sentra B18 (2020-2025) Service Manual: Power Supply and Ground Circuit (ecm)

Nissan Sentra B18 (2020-2025) Service Manual / Engine / Work Procedure (After Replacing Electric Throttle Control Actuator) / Component Parts /circuit Diagnosis / Power Supply and Ground Circuit (ecm)

Diagnosis Procedure

Diagnosis Procedure

CHECK THE BATTERY CABLE
1. Turn ignition switch OFF.
2. Check the battery cable for tightening enough.
  Note:
  Check the continuity between the battery cable and the battery terminal.
Is the inspection result normal?
YES >>
GO TO 2.
NO >>
Repair or replace battery cable connection.
CHECK ECM INTERMITTENT INCIDENT

Check intermittent incident. Refer to Intermittent Incident.

Is the inspection result normal?
YES >>
GO TO 3.
NO >>
Repair or replace ECM connection.

CHECK FUSE

Turn ignition switch OFF.

Check that the following fuse is not blowing.

Location	Fuse No.	Capacity
IPDM E/R	#71	10A
	#80	15A
	#91	5A

Is the fuse blown (open)?

YES >>

If the replaced fuse is blown again. Check IPDM E/R power supply.

NO >>

GO TO 4.

CHECK GROUND CONNECTION

Check ground connection E9 and E15. Refer to Circuit Inspection.

Is the inspection result normal?
YES >>
GO TO 5.
NO >>
Repair or replace ground connection.

CHECK ECM GROUND CIRCUIT

Disconnect ECM harness connector.

Check the continuity between ECM harness connector and ground.

ECM		—	Continuity
Connector	Terminal	—	Continuity
F24	5	Ground	Existed
F24	65
F25	69
E16	157
	159
	162

Also check harness for short to power.

Is the inspection result normal?

YES >>

GO TO 6.

NO >>

Repair or replace malfunctioning part.

CHECK ECM POWER SUPPLY-1

Reconnect ECM harness connector.
Turn ignition switch ON.

Check the voltage between ECM harness connector and ground.

ECM	Voltage (Approx.)
E16	155	162	Battery voltage

ECM

Voltage

(Approx.)

Connector

−

Terminal

E16

155

162

Battery voltage

Is the inspection result normal?

YES >>

GO TO 7.

NO >>

GO TO 8.

CHECK ECM POWER SUPPLY-2

Check the voltage between ECM harness connector and ground.

ECM	Condition	Voltage (Approx.)
E16	155	162	Ignition switch ON → OFF	After turning ignition switch OFF, battery voltage will exist for a few seconds and drop to approximately 0 V.

ECM

Condition

Voltage

(Approx.)

Connector

−

Terminal

E16

155

162

Ignition switch ON → OFF

After turning ignition switch OFF, battery voltage will exist for a few seconds and drop to approximately 0 V.

Is the inspection result normal?

YES >>

GO TO 11.

NO >>

GO TO 9.

CHECK ECM POWER SUPPLY CIRCUIT

Turn ignition switch OFF.
Disconnect ECM harness connector.
Disconnect IPDM E/R harness connector.

Check the continuity between ECM harness connector and IPDM E/R harness connector.

ECM		IPDM E/R		Continuity
Connector	Terminal	Connector	Terminal	Continuity
E16	155	F96	73	Existed

Also check harness for short to power.

Is the inspection result normal?

YES >>

GO TO 9.

NO >>

Repair or replace malfunctioning part.

CHECK ECM RELAY CONTROL SIGNAL

Check the voltage between ECM harness connector terminals as per the following.

+	−	Condition	Voltage (Approx.)
Connector	Terminal	Connector	Terminal	Ignition switch ON	0 V
F25	74	E16	162	Turn ignition switch OFF and wait at least 10 seconds.	Battery voltage

−

Condition

Voltage

(Approx.)

ECM

Connector

Terminal

Connector

Terminal

Ignition switch ON

0 V

F25

E16

162

Turn ignition switch OFF and wait at least 10 seconds.

Battery voltage

Is the inspection result normal?

YES >>

GO TO 12.

NO >>

GO TO 10.

CHECK ECM RELAY CONTROL CIRCUIT

Turn ignition switch OFF.
Disconnect ECM harness connector.
Disconnect IPDM E/R harness connector.

Check the continuity between ECM harness connector and IPDM E/R harness connector.

ECM		IPDM E/R		Continuity
Connector	Terminal	Connector	Terminal	Continuity
F25	74	F98	93	Existed

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

Is the inspection result normal?

YES >>

Replace IPDM E/R. Refer to Removal and Installation.

NO >>

Repair or replace malfunctioning part.

CHECK IGNITION SWITCH SIGNAL

Turn ignition switch ON.

Check the voltage between ECM harness connector terminals.

ECM			Condition	Voltage (Approx.)
Connector	+	−
Connector	Terminal
E16	143	162	Ignition switch OFF	0 V
E16	143	162	Ignition switch ON	Battery voltage

Is the inspection result normal?

YES >>

GO TO 13.

NO >>

GO TO 12.

CHECK IGNITION SWITCH SIGNAL CIRCUIT

Turn ignition switch OFF.
Disconnect ECM harness connector.
Disconnect IPDM E/R harness connector.

Check the continuity between ECM harness connector and IPDM E/R harness connector.

+		−		Continuity
ECM		IPDM E/R
Connector	Terminal	Connector	Terminal
E16	143	E43	19	Existed

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

Is the inspection result normal?

YES >>

Perform trouble diagnosis for power supply.

NO >>

Repair or replace malfunctioning part.

CHECK ECM POWER SUPPLY (BACK-UP)

Check the voltage between ECM harness connector terminals.

ECM				Voltage
+		−
Connector	Terminal	Connector	Terminal
F25	123	E16	162	Battery voltage

Is the inspection result normal?

YES >>

Check intermittent incident. Refer to Intermittent Incident.

NO >>

GO TO 14.

CHECK ECM POWER SUPPLY (BACK-UP) CIRCUIT

Turn ignition switch OFF.
Disconnect ECM harness connector.
Pull out 10 A fuse (No.71).

Check the continuity between ECM harness connector and fuse.

ECM		Fuse No.	Continuity
Connector	Terminal	Fuse No.	Continuity
F25	123	71	Existed

Also check harness for short to ground.

Is the inspection result normal?

YES >>

Perform the trouble diagnosis for battery power supply circuit.

NO >>

Repair or replace error-detected parts.

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