P0122
P0122 - APPS SIGNAL 1 CIRCUIT LOW
When Monitored and Set Condition
- When Monitored: With the ignition on and no other Accelerator Pedal Position (APP) Sensor 1 DTCs present.
- Set Condition: When the APP Sensor Signal 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.
Diagnostic Test
1. PRE-DIAGNOSTIC CHECK OUT
NOTE: Always perform diagnostics with a fully charged battery.
NOTE: Check connectors - Clean/repair as necessary. Poor pin to terminal connections can set DTCs.
NOTE: Check for applicable TSBs related to the problem.
Turn the ignition on.
With the DRB III(R), read PCM DTCs.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. Repair as necessary.
Perform this procedure prior to symptom diagnosis.
Continue
- Go To 2
2. CHECK THE APP SENSOR VOLTAGE
Turn the ignition on.
With the DRB III(R), read the APP 1 voltage.
Is the voltage below 0.3 volt?
Yes
- Go To 3
No
- Go To 10
3. APP SENSOR 5-volt SUPPLY CIRCUIT
Turn the ignition off.
Disconnect the APP Sensor harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Turn the ignition on.
Measure the voltage of the APP Sensor 5-volt Supply circuit at the APP Sensor harness connector.
Is the voltage between 4.7 and 5.2 volts?
Yes
- Go To 4
No
- Go To 8
4. APP SENSOR
With the ignition on.
Connect a jumper wire between the APP Sensor 5-volt Supply circuit and the APP Sensor Signal 1 circuit in the APP Sensor harness connector.
With the DRB III(R), read the APP 1 voltage.
NOTE: Remove the jumper wire after this step has been completed.
Is the voltage above 4.7 volts?
Yes
- Replace the Accelerator Pedal Position Sensor.
- Perform POWERTRAIN VERIFICATION TEST - VER 2. Powertrain Verification Test - Ver 2
No
- Go To 5
5. APP SENSOR SIGNAL 1 CIRCUIT SHORT TO GROUND
Turn the ignition off.
Disconnect the PCM C4 harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between ground and the APP Sensor Signal 1 circuit.
Is the resistance above 100 kohms?
Yes
- Go To 6
No
- Repair the APP Sensor Signal 1 circuit for a short to ground.
- Perform POWERTRAIN VERIFICATION TEST - VER 2. Powertrain Verification Test - Ver 2
6. APP SENSOR SIGNAL 1 CIRCUIT SHORT TO SENSOR GROUND CIRCUIT(S)
With the ignition off.
Measure the resistance between the Sensor Ground circuits and the APP Sensor Signal 1 circuit.
Is the resistance above 100 kohms?
Yes
- Go To 7
No
- Repair the APP Sensor Signal 1 circuit for a short to the Sensor Ground circuit(s).
- Perform POWERTRAIN VERIFICATION TEST - VER 2. Powertrain Verification Test - Ver 2
7. APP SENSOR SIGNAL CIRCUIT OPEN
With the ignition off.
Measure the resistance of the APP Sensor Signal 1 circuit from the APP Sensor harness connector to the PCM C4 harness connector.
Is the resistance below 5.0 ohms?
Yes
- Go To 9
No
- Repair the APP Sensor Signal circuit for an open.
- Perform POWERTRAIN VERIFICATION TEST - VER 2. Powertrain Verification Test - Ver 2
8. APP SENSOR 5-volt SUPPLY CIRCUIT OPEN
With the ignition on.
Measure the resistance of the APP Sensor 5-volt Supply circuit from the APP Sensor harness connector to the PCM C4 harness connector.
Is the resistance below 5.0 ohms?
Yes
- Go To 9
No
- Repair the APP Sensor 5-volt Supply circuit for an open.
- Perform POWERTRAIN VERIFICATION TEST - VER 2. Powertrain Verification Test - Ver 2
9. 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.
- Perform POWERTRAIN VERIFICATION TEST - VER 2. Powertrain Verification Test - Ver 2
10. CHECK THE APP SENSOR SWEEP
With the ignition on.
With the DRB III(R), monitor the APP 1 voltage.
Slowly open the throttle from the idle position to the wide open throttle position.
Does voltage start at approximately 0.3 volt and go above 4.5 volts with a smooth transition?
Yes
- Go To 11
No
- Replace the Accelerator Pedal Position Sensor.
- Perform POWERTRAIN VERIFICATION TEST - VER 2. Powertrain Verification Test - Ver 2
11. 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 DTCs.
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. 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.