Nissan Xterra. Manual - part 311

EC-370

< DTC/CIRCUIT DIAGNOSIS >

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P0850 PNP SWITCH

Overall Function Check

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Use this procedure to check the overall function of the park/neutral position (PNP) signal circuit. During this

check, a 1st trip DTC might not be confirmed.

 WITH GST

1. Turn ignition switch ON.

2. Check voltage between ECM terminal 117 (PNP signal) and ground under the following conditions.

3. If NG, go to 

EC-370, "Diagnosis Procedure"

.

Diagnosis Procedure

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A/T MODELS

1.

CHECK DTC WITH TCM

Refer to 

TM-177, "DTC Inspection Priority Chart"

.

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace.

2.

CHECK STARTING SYSTEM

Turn ignition switch OFF, then turn it to START.

Does starter motor operate?
Yes or No

Yes

>> GO TO 3.

No

>> Refer to 

STR-9, "A/T : System Diagram"

.

3.

CHECK PNP INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-I

1. Turn ignition switch OFF.

2. Disconnect A/T assembly harness connector.

3. Disconnect combination meter harness connector.

4. Check harness continuity between A/T assembly terminal 9 and combination meter terminal 17.

Refer to Wiring Diagram.

5. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 5.

NG

>> GO TO 4.

4.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors M31, E152

• Harness connectors E5, F14

• Harness for open or short between A/T assembly and combination meter.

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

5.

CHECK PNP INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-II

1. Disconnect ECM harness connector.

2. Check harness continuity between ECM terminal 117 and combination meter terminal 7.

Condition (Gear position)

Voltage V (Known-good data)

P or N position (A/T)
Neutral position (M/T)

Approx. 0

Except above position

BATTERY VOLTAGE

(11 - 14V)

Continuity should exist.

P0850 PNP SWITCH

EC-371

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Refer to Wiring Diagram.

3. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 7.

NG

>> GO TO 6.

6.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors E152, M31

• Harness for open or short between ECM and combination meter

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

7.

CHECK PNP INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-III

1. Check harness continuity between A/T assembly terminal 9 and TCM terminal 8.

Refer to Wiring diagram.

2. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 8.

NG

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

8.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-40, "Intermittent Incident"

.

OK or NG

OK

>> GO TO 9.

NG

>> Repair or replace.

9.

REPLACE COMBINATION METER

Refer to 

MWI-84, "Removal and Installation"

.

>> INSPECTION END

M/T MODELS

1.

CHECK PNP SWITCH GROUND CIRCUIT

1. Turn ignition switch OFF.

2. Disconnect park/neutral position (PNP) switch harness connector.

3. Check harness continuity between PNP switch terminal 2 and ground.

Refer to Wiring Diagram.

4. Also check harness for short to power.
OK or NG

OK

>> GO TO 3

NG

>> GO TO 2.

2.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors F14, E5

• Harness for open or short between PNP switch and ground

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

Continuity should exist.

Continuity should exist.

Continuity should exist.

EC-372

< DTC/CIRCUIT DIAGNOSIS >

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P0850 PNP SWITCH

3.

CHECK PNP SWITCH INPUT SIGNAL CIRCUIT

1. Disconnect ECM harness connector.

2. Check harness continuity between ECM terminal 117 and PNP switch terminal 1.

Refer to Wiring Diagram.

3. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 5.

NG

>> GO TO 4.

4.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors E5, F14

• Harness for open or short between PNP switch and ECM

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

5.

CHECK PNP SWITCH

Refer to 

EC-91, "Wiring Diagram"

.

OK or NG

OK

>> GO TO 6.

NG

>> Replace PNP switch. Refer to 

TM-24, "Overhaul"

.

6.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-40, "Intermittent Incident"

.

>> INSPECTION END

Continuity should exist.

P1148, P1168 CLOSED LOOP CONTROL

EC-373

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P1148, P1168 CLOSED LOOP CONTROL

On Board Diagnosis Logic

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These self-diagnoses have the one trip detection logic.

DTC P1148 or P1168 is displayed with another DTC for air fuel ratio (A/F) sensor 1.

Perform the trouble diagnosis for the corresponding DTC.

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P1148
1148
(Bank 1)

Closed loop control 
function

The closed loop control function for bank 1 does 
not operate even when vehicle is being driven 
in the specified condition.

• Harness or connectors

[The air fuel ratio (A/F) sensor 1 circuit is 
open or shorted.]

• Air fuel ratio (A/F) sensor 1
• Air fuel ratio (A/F) sensor 1 heater

P1168
1168
(Bank 2)

The closed loop control function for bank 2 does 
not operate even when vehicle is being driven 
in the specified condition.