P0122
(P0122) APPS SIGNAL #1 CIRCUIT LOW
When Monitored and Set Condition
^ When Monitored: With the ignition on and no other Accelerator Pedal Position Sensor (APPS) #1 DTCs present.
^ Set Condition: When the APPS #1 voltage is too low. Engine will only idle if the Brake pedal is pressed or has failed. Acceleration rate and Engine output are limited.
POSSIBLE CAUSES
ACCELERATOR PEDAL POSITION SENSOR (APPS) #1 SWEEP
5-VOLT SUPPLY CIRCUIT OPEN
5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
ACCELERATOR PEDAL POSITION SENSOR #1 SIGNAL CIRCUIT OPEN
ACCELERATOR PEDAL POSITION SENSOR #1 SIGNAL CIRCUIT SHORTED TO GROUND
ACCELERATOR PEDAL POSITION SENSOR #1 SIGNAL CIRCUIT SHORTED TO SENSOR
RETURN CIRCUIT
ACCELERATOR PEDAL POSITION SENSOR
POWERTRAIN CONTROL MODULE
Diagnostic Test
1. APPS BELOW 0.25 OF A VOLT
Turn the ignition on.
With the DRB III, read the APPS #1 voltage.
Is the voltage below 0.25 of a volt?
Yes>> Go To 2
No>> Go To 9
2. 5-VOLT SUPPLY CIRCUIT
Turn the ignition off. Disconnect the APPS harness connector.
Note: Check connectors-Clean/repair as necessary.
Turn the ignition on.
Measure the voltage of the 5-Volt Supply circuit at the APPS harness connector.
Is the voltage between 4.5 and 5.2 volts?
Yes>> Go To 3
No>> Go To 6
3. APPS
With the ignition on. Connect a jumper wire between the 5-Volt Supply circuit and the APPS #1 Signal circuit in the Sensor harness connector.
With the DRB III, monitor the APPS #1 voltage.
Note: Remove the jumper wire after this step has been completed.
Is the voltage above 4.5 volts?
Yes>> Replace the APPS in accordance with the Service Information.
Perform Powertrain Verification Test - Ver 2
No>> Go To 4
4. APPS #1 SIGNAL CIRCUIT OPEN
Turn the ignition off.
Disconnect the PCM C4 harness connectors.
Note: Check connectors-Clean/repair as necessary. Measure the resistance of the APPS #1 Signal circuit from the APPS harness connector to the PCM C4 harness connector terminal.
Is the resistance below 5.0 ohms?
Yes>> Go To 5
No>> Repair the APPS #1 Signal circuit for an open.
Perform Powertrain Verification Test - Ver 2
5. APPS SIGNAL CIRCUIT SHORTED TO GROUND
With the ignition off.
Measure the resistance between ground and the APPS #1 Signal circuit.
Is the resistance below 100 ohms?
Yes>> Repair the APPS #1 Signal circuit for a short to ground.
Perform Powertrain Verification Test - Ver 2
No>> Go To 8
6. 5-VOLT SUPPLY CIRCUIT OPEN
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection.
Perform diagnosis by back probing the terminals of each connector.
With the ignition on.
Measure the resistance of the 5-Volt Supply circuit from the APPS Sensor harness connector to the PCM C4 harness connector.
Is the resistance below 5.0 ohms?
Yes>> Go To 7
No>> Repair the 5-Volt Supply circuit for an open.
Perform Powertrain Verification Test - Ver 2
7. 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
With the ignition on.
Measure the resistance between ground and the 5-Volt Supply circuit.
Is the resistance below 100 ohms?
Yes>> Repair the 5-Volt Supply circuit for a short to ground.
Perform Powertrain Verification Test - Ver 2
No>> Go To 8
8. PCM
Note: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
If there are no possible causes remaining, view repair.
Repair>> Replace and program the Powertrain Control Module in accordance with the Service Information.
Perform Powertrain Verification Test - Ver 2
9. APPS SWEEP
With the ignition on.
With the DRB III, monitor the APPS #1 voltage.
Slowly open the throttle from the idle position to the wide open throttle position.
Does voltage start at approximately 0.25 of a volt and go above 4.0 volts with a smooth transition?
Yes>> Go to 10
Perform Powertrain Verification Test - Ver 2
No>> Replace the APPS in accordance with the Service Information.
Perform Powertrain Verification Test - Ver 2
10. INTERMITTENT WIRING AND CONNECTORS
The condition that caused this DTC to set is currently not present. Inspect the related wiring harness for a possible intermittent condition.
Note: Check connectors-Clean/repair as necessary. Poor pin to terminal connections can set DTC's.
Note: Check for any Technical Service Bulletins that may apply. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors specific to this DTC. Wiggle the wires while checking for shorts and open circuits.
Were there any problems found?
Yes>> Repair as necessary.
Perform Powertrain Verification Test - Ver 2
No>> The condition that caused this DTC to set is currently not present. Inspect the related wiring harness for a possible intermittent condition.