Nissan Murano: Dtc/circuit Diagnosis / P2256 A/f Sensor 1

DTC Description

DTC DETECTION LOGIC

To judge malfunctions, the diagnosis checks that the A/F signal computed by ECM from the A/F sensor 1 signal fluctuates according to fuel feedback control.

1. The A/F signal computed by ECM from the A/F sensor 1 signal is constantly in a range other than approx. 2.2 V.

2. The A/F signal computed by ECM from the A/F sensor 1 signal is constantly approx. 2.2 V.

POSSIBLE CAUSE

P2256 - 1

• Harness or connectors (The A/F sensor 1 circuit is open or shorted.)

• A/F sensor 1

P2256 - 2

• Harness or connectors (The A/F sensor 1 circuit is open or shorted.)

• A/F sensor 1

FAIL-SAFE

Not applicable

PRECONDITIONING

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

1. Turn ignition switch OFF and wait at least 10 seconds.

2. Turn ignition switch ON.

3. Turn ignition switch OFF and wait at least 10 seconds.

TESTING CONDITION:

Before performing the following procedure, confirm that battery voltage is more than 11 V at idle.

GO TO 2.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION 1

1. Start engine and warm it up to normal operating temperature.

2. Let engine idle for 2 minutes.

3. Check 1st trip DTC.

Is 1st trip DTC detected?

Proceed to Diagnosis Procedure.

With CONSULT: GO TO 3.

With GST: GO TO 7.

CHECK AIR FUEL RATIO (A/F) SENSOR 1 FUNCTION

1. Start engine and warm it up to normal operating temperature.

2. Select “A/F SEN1 (B2)” in “DATA MONITOR” mode with CONSULT.

3. Check “A/F SEN1 (B2)” indication.

Does the indication fluctuate around 2.2 V?

GO TO 4.

Proceed to Diagnosis Procedure.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION 2-I

1. Select “A/F SEN1 (B2) P1286” (for DTC P2256) of “A/F SEN1” in “DTC WORK SUPPORT” mode with CONSULT.

2. Touch “START”.

3. When the following conditions are met, “TESTING” will be displayed on the CONSULT screen.

   ENG SPEED	1,000 - 3,200 rpm
   VHCL SPEED SE	More than 64 km/h (40 mph)
   B/FUEL SCHDL	1.0 - 10.0 msec
   Selector lever	D position

   If “TESTING” is not displayed after 20 seconds, retry from step 2.

   CAUTION:

   Always drive Nissan Murano vehicle at a safe speed.

Is “TESTING” displayed on CONSULT screen?

GO TO 5.

Check A/F sensor 1 function again. GO TO 3.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION 2-II

Release accelerator pedal fully.

NOTE:

Never apply brake when releasing the accelerator pedal.

Which does “TESTING” change to?

GO TO 6.

Retry DTC CONFIRMATION PROCEDURE. GO TO 4.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION 2-III

Touch “SELF-DIAG RESULT”.

Which is displayed on CONSULT screen?

To check malfunction symptom before repair: Refer to Intermittent Incident.

Confirmation after repair: INSPECTION END

Proceed to Diagnosis Procedure.

PERFORM COMPONENT FUNCTION CHECK

With GST

1. Start engine and warm it up to normal operating temperature.

2. Drive the Nissan Murano vehicle at a speed of 80 km/h (50 MPH) for a few minutes in the suitable gear position.

3. Shift the selector lever to the D position, then release the accelerator pedal fully until the Nissan Murano vehicle speed decreases to 50 km/h (31 MPH).

   CAUTION:

   Always drive vehicle at a safe speed.

   NOTE:

   Never apply brake when releasing the accelerator pedal.

4. Repeat steps 2 and 3 for 5 times.

5. Stop the Nissan Murano vehicle and turn ignition switch OFF.

6. Wait at least 10 seconds and restart engine.

7. Repeat steps 2 and 3 for 5 times.

8. Stop the Nissan Murano vehicle.

9. Check 1st trip DTC.

Is 1st trip DTC detected?

Proceed to Diagnosis Procedure.

To check malfunction symptom before repair: Refer to Intermittent Incident.

Confirmation after repair: INSPECTION END

CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY

1. Disconnect A/F sensor 1 harness connector.

2. Turn ignition switch ON.

3. Check the voltage between A/F sensor 1 harness connector and ground.

   A/F sensor 1			Ground	Voltage
   Bank	Connector	Terminal
   2	F61	1	Ground	Battery voltage

Is the inspection result normal?

GO TO 3.

GO TO 2.

CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT

1. Turn ignition switch OFF.

2. Disconnect IPDM E/R harness connector.

3. Check the continuity between A/F sensor 1 harness connector and IPDM E/R harness connector.

Is the inspection result normal?

Perform the trouble diagnosis for power supply circuit.

Repair or replace error-detected parts.

CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT

1. Turn ignition switch OFF.

2. Disconnect ECM harness connector.

3. Check the continuity between A/F sensor 1 harness connector and ECM harness connector .

   A/F sensor 1			ECM		Continuity
   Bank	Connector	Terminal	Connector	Terminal
   2	F61	3	F79	76	Existed
   		4		77

4. Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector and ground.

   A/F sensor 1			Ground	Continuity
   Bank	Connector	Terminal
   2	F61	3	Ground	Not existed
   		4

   ECM		Ground	Continuity
   Connector	Terminal
   F79	76	Ground	Not existed
   	77

5. Also check harness for short to power.

Is the inspection result normal?

INSPECTION END

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