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.
POSSIBLE CAUSES
- 5-VOLT SUPPLY CIRCUIT OPEN
- ACCELERATOR PEDAL POSITION SENSOR SIGNAL 1 CIRCUIT OPEN
- ACCELERATOR PEDAL POSITION SENSOR SIGNAL 1 CIRCUIT SHORT TO GROUND
- ACCELERATOR PEDAL POSITION SENSOR SIGNAL 1 CIRCUIT SHORT TO SENSOR GROUND CIRCUIT(S)
- ACCELERATOR PEDAL POSITION SENSOR
- POWERTRAIN CONTROL MODULE
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 DRBIII, 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 DRBIII, 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 DRBIII, 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 DRBIII, 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.