Diagnostic Procedure
WARNING: This page is about a different car, the 2002 Nissan Pathfinder and 2002 Infiniti QX4. However, it is still accessible from the selected car via links, so may be relevant.
- Turn ignition off. Disconnect Throttle Position (TP) switch 6-pin harness connector. Turn ignition on. Measure voltage between ground and TP switch harness connector terminal No. 5 (Red/Yellow wire). See Figure . If battery voltage does not exist, go to next step. If battery voltage exists, go to step 3 .
- Check following:
- Check for poor, loose, corroded or damage to terminal connections in in-line harness connectors F23 and M32. See WIRING DIAGRAMS article.
- Check for open or short in circuits between ECM and TP switch.
- Turn ignition off. Disconnect ECM 116-pin harness connector. For ECM location, see Figure . Check continuity in Orange/Blue wire between ECM harness connector terminal No. 56 and TP switch harness connector terminal No. 6. See Figure . Continuity should exist. Also, check circuit for short to ground or short to voltage. If no problem is found, go to next step. If problem is found, repair as necessary. After repair, repeat appropriate DTC CONFIRMATION TEST.
- Check ignition timing and engine speed. See THROTTLE POSITION SWITCH, IGNITION TIMING & IDLE SPEED in ON-VEHICLE ADJUSTMENTS article. If using CONSULT-II, go to next step. Using generic scan tool, go to step 6 .
- Start engine and warm to normal operating temperature. Turn ignition off, and then on. Select DATA MONITOR mode on CONSULT-II. Check CLSD THL/P SW parameter under following conditions, see CHECKING THROTTLE POSITION SWITCH SIGNAL
table. Measurement must be made with TP switch installed in vehicle. If CLSD THL/P SW parameter is as specified, go to step 8
. If parameter is not as specified, go to step 7
.CHECKING THROTTLE POSITION SWITCH SIGNAL
Throttle Valve Position CLSD THL/P SW Closed ON Partially Open OFF - Start engine and warm to normal operating temperature. Turn ignition off. Disconnect TP switch 6-pin harness connector. Check continuity between TP sensor harness connector terminals No. 5 (Red/Yellow wire) and No. 6 (Orange/Blue wire). See Figure . Measurement must be made with TP switch installed in vehicle. With throttle closed continuity should exist. With throttle partially open no continuity should exist. If continuity is as specified, go to next step. If continuity is not as specified, go to step 9 .
- Check TP switch adjustment. See THROTTLE POSITION SWITCH, IGNITION TIMING & IDLE SPEED in ON-VEHICLE ADJUSTMENTS article. If TP switch is adjustable, go to step 9 . If TP switch is not adjustable, replace TP switch. After repair, repeat appropriate DTC CONFIRMATION TEST.
- Start engine and warm to normal operating temperature. Turn ignition off, and then on. Select DATA MONITOR mode on CONSULT-II. THRTL POS SEN voltage should be as specified. See CHECKING THROTTLE POSITION SWITCH VOLTAGE (WITH CONSULT-II)
table. Measurement must be made with TP switch installed in vehicle. If voltage is as specified, go to step 10
. If voltage is not as specified, replace TP sensor. After repair, repeat appropriate DTC CONFIRMATION TEST.CHECKING THROTTLE POSITION SWITCH VOLTAGE (WITH CONSULT-II)
Throttle Valve Position THRTL POS SEN Voltage Fully Closed .15-.85 Volts Partially Open .15-4.7 Volts Fully Open 3.5-4.7 Volts - Start engine and warm to normal operating temperature. Turn ignition off, and then on. Backprobbing at ECM, measure voltage between ground and ECM terminal No. 91 (Red wire). See Figure
. Voltage should be as specified. See CHECKING THROTTLE POSITION SWITCH VOLTAGE
table. If voltage is as specified, go to next step. If voltage is not as specified, replace TP sensor. After repair, repeat appropriate DTC CONFIRMATION TEST.CHECKING THROTTLE POSITION SWITCH VOLTAGE
Throttle Valve Position Throttle Position Switch Voltage Fully Closed .15-.85 Volts Partially Open .15-4.7 Volts Fully Open 3.5-4.7 Volts - No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.