019-086   Accelerator Pedal or Lever Position Sensor Circuit

CAUTION  To reduce the possibility of connector damage, do not use probes or leads other than Part Number 3822758. The leads must fit tightly in the connector without expanding the pins in the connector.

If INSITE™ is available, monitor the accelerator position sensor circuit for proper operation. If not , follow the troubleshooting procedures in this section. Disconnect the OEM harness connector from the ECM. Refer to Procedure 019-071. Make sure the sensor is connected to the OEM harness.

Insert a test lead into pin 18 (+5-VDC supply) of the OEM harness connector. Insert the other test lead into pin 19 (return).

Connect the alligator clips to the multimeter probes. Measure the resistance. The multimeter must show 2000 to 3000 ohms when the accelerator pedal is up or down. If the resistance is not within the specification, there is a problem with pin 18 or pin 19 in the OEM harness connector, provided the accelerator position sensor has been previously checked. Repair the OEM harness according to the manufacturer’s procedures.

Remove the test lead from pin 19 (return ground) and insert it into pin 11 (signal return).

Make sure the foot pedal is in the released (idle) position.

Measure the resistance. The multimeter must show 1500 to 3000 ohms.

Depress the foot pedal (full fuel) and measure the resistance again. The multimeter must show 250 to 1500 ohms. This resistance value must
be at least 1000 ohms lower than the resistance value of 1500 to 3000 ohms measured in the previous check. If the resistance values are not within the specification, there is a problem with pin 18 (+5-VDC supply) or pin 11 (return signal) in the OEM harness. Repair the OEM harness according to the manufacturer’s procedures. If the resistance values in the two previous checks are within the specification, pin 11, pin 18, and pin 19 must still be checked for a short circuit to ground, a short circuit from pin to pin, and a short circuit to battery supply.

NOTE: When checking the OEM harness, examine the bulkhead connector and other connectors in the circuit for corrosion or damage to the accelerator pedal sensor wire terminals.

Disconnect the accelerator position sensor from the OEM harness at the foot pedal assembly.

Insert a test lead into pin 18 (+5-VDC supply). Connect the clip to the multimeter positive probe. Touch the multimeter negative probe to the engine block ground and measure the resistance.

The multimeter must show an open circuit (100k ohms or more).

Remove the test lead from pin 18 and insert it into pin 19 (return ground). Touch the multimeter negative probe to the engine block ground and measure the resistance.

The multimeter must show an open circuit (100k ohms or more).

Remove the test lead from pin 19 and insert it into pin 11 (signal return). Touch the multimeter negative probe to the engine block ground and measure the resistance. The multimeter must show an open circuit (100k ohms or more).

If any of these three resistance measurements are not open, there is a short circuit to ground between the wires connected to pin 18, 19, or 11. Repair the OEM harness according to the vehicle manufacturer’s procedures.

Connect the accelerator position sensor when the repair is completed.

Disconnect the accelerator position sensor from the OEM harness at the foot pedal assembly.

Insert a test lead into pin 18 (+5-VDC supply). Place the other test lead into pin 1. Connect the clips to the multimeter probes and measure the resistance.

The multimeter must show an open circuit (100k ohms or more).

Remove the test lead from pin 1 and insert it into pin 2, then pin 3.

The multimeter must show an open circuit (100k ohms or more)
in all pins.

If the multimeter shows a closed circuit at any pin, there is a short circuit between pin 18 and any other wire that measured a closed circuit. Repair the OEM harness according to the vehicle manufacturer’s procedures.

Remove the test lead from pin 18 and insert it into pin 19 (return ground). Place the other test lead into pin 1 and measure the resistance.

The multimeter must show an open circuit (100k ohms or more).

Remove the test lead from pin 1 and insert it into pin 2, then pin 3.

The multimeter must show an open circuit (100k ohms or more)
in all pins.

Remove the test lead from pin 19 and insert it into pin 11 (signal return). Place the other test lead into pin 1 and measure the resistance.

The multimeter must show an open circuit (100k ohms or more).

Remove the test lead from pin 1 and insert it into pin 2, then pin 3.

The multimeter must show an open circuit (100k ohms or more)
in all pins.

If the multimeter shows a closed circuit at any pin, there is a short circuit between pin 11 and any other wire that measured a closed circuit. Repair the OEM harness according to the vehicle manufacturer’s procedures.

Connect the accelerator position sensor when the repair is completed.

Disconnect the accelerator position sensor from the OEM harness at the foot pedal assembly.

Turn keyswitch ON. Adjust the multimeter to measure DC voltage. Insert a test lead into pin 18 (+5-VDC supply). Connect the clip to the multimeter positive probe. Connect the multimeter negative probe to the engine block ground and measure the voltage.

The voltage must be 1.5 VDC or less.

Remove the test lead from pin 18 and insert it into pin 19 (return ground). Touch the multimeter negative probe to the engine block ground and measure the voltage.

The voltage must be 1.5 VDC or less.

Remove the test lead from pin 19 and insert it into pin 11 (signal return). Touch the multimeter negative probe to the engine block ground and measure the voltage.

The voltage must be 1.5 VDC or less.

If more than 1.5 VDC are measured at any pin, there is a short circuit from pin 18, 19, or 11 to a wire carrying power in the OEM harness. Repair the OEM harness according to the vehicle manufacturer’s procedures. Connect the accelerator position sensor when the repair is completed.

NOTE: The external voltage source is any wire in the OEM harness that carries voltage.

Connect all components after the repair is complete.