1996 PCED OBDI | SECTION 18: Diesel Diagnosis — 7.3L DI Engine |
E1 DIAGNOSTIC TROUBLE CODE (DTC) 0123
- DTC 0123 indicates AP sensor circuit high input.
- Possible causes are:
- Damaged accelerator pedal assembly
- AP sensor may not be seated properly (tightened down)
- Damaged AP sensor
- Short to power in harness
- Damaged PCM
- Key on, engine off.
- NGS Tester installed.
- Access AP PID (voltage).
- Slowly depress accelerator pedal while observing voltage reading on NGS Tester.
Does reading go above 4.5v?
Yes | No |
GO to E2. | CLEAR DTCs and RETEST. |
E2 INDUCE OPPOSITE FAILURE
- Disconnect AP sensor connector. Inspect for damaged, pushed-out or corroded pins. Repair as necessary.
Does AP voltage reading on NGS Tester read 0v?
Yes | No |
Circuit OK. REPLACE accelerator pedal assembly. CLEAR DTCs and RETEST. | GO to E3. |
E3 CHECK AP SENSOR SIGNAL WIRE
- AP sensor disconnected.
- Key on, engine off.
- Measure voltage between AP signal wire at harness connector to ground.
Is voltage above 4.5v?
Yes | No |
GO to E4. | REPLACE PCM. Internal failure. CLEAR DTCs and RETEST. |
E4 CHECK AP CIRCUIT FOR SHORTS TO POWER
- Key off.
- AP sensor disconnected.
- Disconnect PCM. Inspect for damaged or pushed-out pins, corrosion, loose wires, etc. Service as necessary.
- Install breakout box, leave PCM disconnected.
- Key on, engine off.
- Measure voltage between Test Pin 89 and ground at the breakout box.
Is voltage present?
Yes | No |
REPAIR short to power in Circuit 355 (GY/W). CLEAR DTCs and RETEST. | REPLACE PCM. Internal failure. CLEAR DTCs and RETEST. |
E5 DIAGNOSTIC TROUBLE CODE (DTC) 0122
- DTC 0122 indicates the AP sensor circuit low input.
- Possible causes:
- AP sensor may not be seated properly (tightened down)
- Damaged AP sensor
- Open harness
- Grounded harness
- Damaged PCM
- Key on, engine off.
- NGS Tester installed.
- Access AP PID (voltage).
- Depress accelerator pedal while observing voltage reading on NGS Tester.
Does voltage drop below .37v?
Yes | No |
GO to E6. | Unable to duplicate and/or identify concern at this time. CLEAR DTCs and RETEST. |
E6 INDUCE OPPOSITE FAILURE
- Disconnect AP sensor connector and jumper VREF pin to AP signal wire.
Does NGS Tester display stay on and read over 4.5v?
Yes | No |
REPLACE accelerator pedal assembly. CLEAR DTCs and RETEST. | GO to E7. |
E7 CHECK VREF CIRCUIT VOLTAGE
- Key off.
- AP sensor disconnected.
- Key on, engine off.
- Measure voltage between VREF circuit and ground.
Is voltage 5v ± .5?
Yes | No |
GO to E8. | SERVICE open in VREF Circuit 351 (BR/W). CLEAR DTCs and RETEST. |
E8 CHECK SIGNAL RETURN CIRCUIT
- Key off.
- AP sensor disconnected.
- Measure resistance between signal return and ground.
Is resistance less than 5 ohms?
Yes | No |
GO to E9. | SERVICE open in signal return Circuit 359 (GY/R). CLEAR DTCs and RETEST. |
E9 CHECK AP CIRCUIT CONTINUITY
- Key off.
- AP sensor disconnected.
- Disconnect PCM. Inspect for damaged or pushed-out pins, corrosion, loose wires, etc. Service as necessary.
- Install breakout box, leave PCM disconnected.
- Measure resistance between AP circuit at the vehicle harness connector and Test Pin 89 at the breakout box, to the middle terminal.
Is the resistance less than 5 ohms?
Yes | No |
GO to E10. | SERVICE open in AP signal Circuit 355 (GY/W). REMOVE breakout box. CLEAR DTCs and RETEST. |
E10 CHECK AP CIRCUIT FOR SHORTS TO GROUND
- Key off.
- AP sensor disconnected.
- Disconnect PCM. Inspect for damaged or pushed-out pins, corrosion, loose wires, etc. Service as necessary.
- Install breakout box, leave PCM disconnected.
- Measure resistance between Test Pin 89 and Test Pins 51, 76, 77, 91 and 103 at the breakout box.
Is each resistance greater than 10,000 ohms?
Yes | No |
GO to E11. CLEAR DTCs and RETEST. | SERVICE short to ground in AP sensor signal Circuit 355 (GY/W). CLEAR DTCs and RETEST. REMOVE breakout box. |
E11 VREF CIRCUIT CONTINUITY CHECK
- AP sensor connector disconnected.
- PCM disconnected.
- Measure resistance from VREF circuit at harness connector to Pin 90 at the breakout box.
Is resistance less than 5 ohms?
Yes | No |
GO to E12. | REPAIR open in VREF Circuit 351 (BR/W). CLEAR DTCs and RETEST. |
E12 SIGNAL RETURN CIRCUIT CONTINUITY CHECK
- AP sensor connector disconnected.
- PCM disconnected.
- Measure resistance from signal return circuit at harness connector to Pin 91 at the breakout box.
Is resistance less than 5 ohms?
Yes | No |
REPLACE PCM. CLEAR DTCs and RETEST. | REPAIR open in signal. RETURN Circuit 359 (GY/R). |