P2122-ACCELERATOR PEDAL POSITION SENSOR 1 CIRCUIT LOW
For a complete wiring diagram Refer to Section 8W
Theory of Operation
The Accelerator Pedal Position Sensor contains two independent three wire inductive sensors. Each sensor provides independent pedal position signals to the ECM. The raw voltage signal from APP
#1 sensor is 2 times the raw voltage signal from APP #2. Although the raw voltage signals differ, the scan tool converts and displays these voltages as matching percentages of pedal travel.
Possible Causes
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INTERMITTENT DTC
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(F855) ACCELERATOR PEDAL POSITION SENSOR NO. 1 5 VOLT SUPPLY CIRCUIT OPEN OR HIGH RESISTANCE
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(K23) ACCELERATOR PEDAL POSITION SENSOR NO. 1 SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE
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(K167) ACCELERATOR PEDAL POSITION SENSOR NO. 1 SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCE
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(F855) ACCELERATOR PEDAL POSITION SENSOR NO. 1 5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND
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(K23) ACCELERATOR PEDAL POSITION SENSOR NO. 1 SIGNAL CIRCUIT SHORTED TO GROUND
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(K23) ACCELERATOR PEDAL POSITION SENSOR NO. 1 SIGNAL CIRCUIT SHORTED TO THE (K167) ACCELERATOR PEDAL POSITION SENSOR NO. 1 SENSOR GROUND CIRCUIT
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(K23) ACCELERATOR PEDAL POSITION SENSOR NO. 1 SIGNAL CIRCUIT SHORTED TO THE (K400) ACCELERATOR PEDAL POSITION SENSOR NO. 2 SENSOR GROUND CIRCUIT
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ACCELERATOR PEDAL POSITION SENSOR
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ENGINE CONTROL MODULE (ECM)
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Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
Diagnostic Test
1.
DTC IS ACTIVE
NOTE:
If any Sensor Reference or Sensor Supply voltage DTCs are present, perform the applicable diagnostic procedure before continuing with this test.
NOTE:
The APP Sensor 2 signal should always be approximately 1/2 the voltage of the APP Sensor 1 signal.
Ignition on, engine not running.
With the scan tool, Clear DTCs in the Engine Control Module (ECM).
Fully depress and release the Accelerator Pedal several times.
With the scan tool, select View DTCs.
Is the status Active for this DTC?
Yes
No
2.
ACCELERATOR PEDAL POSITION SENSOR CIRCUIT OPEN OR HIGH RESISTANCE
Turn the ignition off.
Disconnect the APP Sensor harness connector.
Disconnect the Engine Control Module (ECM) harness connector.
Measure the resistance of the (F855) Accelerator Pedal Position Sensor No. 1 5 Volt Supply circuit between the Accelerator Pedal Position Sensor harness connector and the Engine Control Module
(ECM) harness connector.
Measure the resistance of the (K23) Accelerator Pedal Position Sensor No. 1 Signal circuit between the Accelerator Pedal Position Sensor harness connector and the Engine Control Module (ECM)
harness connector.
Measure the resistance of the (K167) Accelerator Pedal Position Sensor No. 1 Sensor Ground circuit between the Accelerator Pedal Position Sensor harness connector and the Engine Control Module
(ECM) harness connector.
Is the resistance below 10.0 ohms for each of the circuits?
Yes
No
3.
ACCELERATOR PEDAL POSITION SENSOR CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (F855) Accelerator Pedal Position Sensor No. 1 5 Volt Supply circuit in the Accelerator Pedal Position Sensor harness connector.
Measure the resistance between ground and the (K23) Accelerator Pedal Position Sensor No. 1 Signal circuit in the Accelerator Pedal Position Sensor harness connector.
Is the resistance between ground and both of the circuits above 1000 ohms?
Yes
No
4.
(K23) ACCELERATOR PEDAL POSITION SENSOR NO. 1 SIGNAL CIRCUIT SHORTED TO THE SENSOR GROUND CIRCUIT
Measure the resistance between the (K23) Accelerator Pedal Position Sensor No. 1 Signal circuit and the (K167) Accelerator Pedal Position Sensor No. 1 Sensor Ground circuit in the Accelerator
Pedal Position Sensor harness connector.
Measure the resistance between the (K23) Accelerator Pedal Position Sensor No. 1 Signal circuit and the (K400) Accelerator Pedal Position Sensor No. 2 Sensor Ground circuit in the Accelerator
Pedal Position Sensor harness connector.
Is the resistance between ground and both of the circuits above 1000 ohms?
Yes
No
5.
ACCELERATOR PEDAL POSITION SENSOR
Connect the Engine Control Module (ECM) harness connector.
Connect a jumper wire between the (F855) Accelerator Pedal Position Sensor No. 1 5 Volt Supply circuit and the (K23) Accelerator Pedal Position Sensor No. 1 Signal circuit in the Accelerator
Pedal Position Sensor harness connector.
Turn the ignition on.
With the scan tool, Clear DTCs.
Fully depress and release the Accelerator Pedal several times.
With the scan tool, select View DTCs.
NOTE:
The scan tool should display an Accelerator Pedal Position Sensor No. 1 high voltage or open DTC with the Accelerator Pedal Position Sensor connector disconnected.
Does the scan tool display the DTC as described above?
Yes
No
6.
ENGINE CONTROL MODULE (ECM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Accelerator Pedal Position Sensor and the Engine Control Module (ECM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
Look for the data to change or for the DTC to reset during the wiggle test.
Refer to any Technical Service Bulletins that may apply.
Were any problems found?
Yes
No