MIL ON - APS DTC Set /Idle Fluctuates

BULLETIN NUMBER:
SB01-04-S001

ISSUE DATE:
JULY 2001

GROUP:
ELECTRICAL

APS DTC IS SET

AFFECTED VEHICLES

2000-2001 Trooper (UX), Rodeo (UE), and Amigo/Rodeo Sport (UA) with Electronic Throttle, equipped with V6 engines

SERVICE INFORMATION

Condition:

The engine may occasionally experience idle fluctuation and/ or the MIL will illuminate because an accelerator position sensor (APS) DTC is set; P1271, P1273, P1275, P1280, or P1285. Also the Reduced Power light may be on.

Possible Cause:

The APS is contaminated with dust and grease, which is affecting the resistance values of both AP1 & AP2.

NOTE:
AP1 and AP2 are inverse signals and should always add up to 100% +/- 1%. A DTC will set when the sum is 95% or less, or 105% or more.

Correction:
Replace and adjust the APS, remove grease from the pedal assembly, clean the electrical connector(s), and check the signal voltage for AP1 using the Tech 2.

SERVICE PROCEDURE

1. Park and secure the vehicle.

2. Turn the ignition key off.





3. Disconnect the harness connector from the Accelerator Position Sensor. (Figure 1)

4. Remove the Accelerator Position Sensor. (Figure 1)

5. Remove all grease residues from the Accelerator Position Sensor mounting.

6. Clean all connector pins with contact cleaner. Use LOCTITE(R) / Permatex Electrical Contact Cleaner, or equivalent.

NOTE:
Do not use brake cleaner or carburetor spray.

7. Allow the connector to dry

NOTE:
Do not apply grease or any other material to the terminal pins.





8. Install the new Accelerator Position Sensor with the screw loose to allow for sensor adjustment. (Figure 2)

IMPORTANT:
Whenever the Accelerator Position Sensor is replaced, the sensor must be adjusted.

9. Install the harness connector to the Accelerator Position Sensor.

10. Install the Tech 2 and turn the key to the "ON" position.

11. Under Engine Data, scroll down to the APT percentage opening value.

12. Adjust the Accelerator Position Sensor (APS) until the percentage of AP1 opening is between 11% and 15%. Tighten the Accelerator Position Sensor screws (Figure 2)

13. Using a DVOM, measure AP1 signal voltage at pin # 5 (white wire) of the APS connector. The set voltage, after the percentage is set, will be 0.6 volts at pin # 5 of the C-48.

NOTE:
Remember the Tech 2 does not give a voltage value For AP1. Please refer to 2000 Rodeo/Amigo, and/or 2000 Trooper Electrical Troubleshooting Manual for circuit schematic.

14. If less than 0.6 volt, troubleshoot for high resistance in the black wire (APS pin # 10) between the APS and PCM, or low reference voltage (should be 5.0 v) from the PCM. Try a known good PCM first.

^ If equal to 0.6 volt, the circuit is functioning properly.

^ If more than 0.6 volt, troubleshoot for high resistance in the red wire (APS pin # 4) between the APS and PCM.





^ After the adjustment is performed please verify the reading shown.

15. Remove the Tech 2 and return the vehicle to the customer.





PARTS INFORMATION





Use the new labor operation shown.

Labor Time includes administrative time allowance.





For your convenience please use the information shown when submitting your warranty claim.





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