P2123-ACCELERATOR PEDAL POSITION SENSOR 1 CIRCUIT HIGH

For a complete wiring diagram, refer to the Wiring Information.

When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
Set Condition:
The Powertrain Control Module (PCM) detects that the APP Sensor 1 input voltage is above the maximum acceptable value.

POSSIBLE CAUSES
(K852) 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
(K23) APP SIGNAL 1 CIRCUIT SHORTED TO VOLTAGE
(K23) APP SIGNAL 1 CIRCUIT SHORTED TO THE (K852) 5-VOLT SUPPLY CIRCUIT
(K23) APP SIGNAL 1 CIRCUIT SHORTED TO THE (K854) 5-VOLT SUPPLY CIRCUIT
(K23) APP SIGNAL 1 CIRCUIT OPEN OR HIGH RESISTANCE
(K167) SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCE
ACCELERATOR PEDAL POSITION SENSOR
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

1. DTC IS ACTIVE

NOTE: Diagnose and repair any system voltage or sensor reference voltage DTCs before continuing with this test.

1.	Start the engine and allow it to reach normal operating temperature.

WARNING:

When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

2.	With the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

Go To 2

Perform the INTERMITTENT CONDITION diagnostic procedure. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

2. (K852) 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE

1.	Turn the ignition off.

2.	Disconnect the Accelerator Pedal Position Sensor harness connector.

3.	Disconnect the Powertrain Control Module (PCM) C1 harness connector.

4.	Turn the ignition on.

5.	Measure the voltage of the (K852) 5-Volt Supply circuit in the Accelerator Pedal Position Sensor harness connector.

Is there any voltage present?

Yes

Repair the (K852) 5-Volt Supply circuit for a short to voltage.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

Go To 3

3. (K23) APP SIGNAL 1 CIRCUIT SHORTED TO VOLTAGE

1.	Measure the voltage of the (K23) APP Signal 1 circuit in the Accelerator Pedal Position Sensor harness connector.

Is there any voltage present?

Yes

Repair the (K23) APP Signal 1 circuit for a short to voltage.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

Go To 4

4. (K23) APP SIGNAL 1 CIRCUIT SHORTED TO THE (K852) 5-VOLT SUPPLY CIRCUIT

1.	Measure the resistance between the (K23) APP Signal 1 circuit and the (K852) 5-Volt Supply circuit in the Accelerator Pedal Position Sensor harness connector.

Is the resistance below 100 Ohms?

Yes

Repair the (K23) APP Signal 1 circuit for a short to the (K852) 5-Volt Supply circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

Go To 5

5. (K23) APP SIGNAL 1 CIRCUIT SHORTED TO THE (K854) 5-VOLT SUPPLY CIRCUIT

1.	Measure the resistance between the (K23) APP Signal 1 circuit and the (K854) 5-Volt Supply circuit in the Accelerator Pedal Position Sensor harness connector.

Is the resistance below 1000 Ohms?

Yes

Repair the (K23) APP Signal 1 circuit for a short to the (K854) 5-Volt Supply circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

Go To 6

6. (K23) APP SIGNAL 1 CIRCUIT OPEN OR HIGH RESISTANCE

1.	Turn the ignition off.

2.	Measure the resistance of the (K23) APP Signal 1 circuit between the Accelerator Pedal Position Sensor harness connector and the PCM C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

Go To 7

Repair the (K23) APP Signal 1 circuit for an open circuit or high resistance.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

7. (K167) SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCE

1.	Measure the resistance of the (K167) Sensor Ground circuit between the Accelerator Pedal Position Sensor harness connector and the PCM C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

Go To 8

Repair the (K167) Sensor Ground circuit for an open circuit or high resistance.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

8. ACCELERATOR PEDAL POSITION SENSOR

1.	Turn the ignition off.

2.	Connect the PCM C1 harness connector.

3.	Connect a jumper wire between the (K167) Sensor Ground circuit and the (K23) APP Signal 1 circuit in the Accelerator Pedal Position Sensor harness connector.

4.	Turn the ignition on.

5.	With the scan tool, read the Accelerator Pedal Position Sensor signal voltage.

Is the voltage below 1.0 volt with the jumper wire in place?

Yes

Replace the Accelerator Pedal Position Sensor in accordance with the Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

Go To 9

9. POWERTRAIN CONTROL MODULE (PCM)

1.	Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Accelerator Pedal Position Sensor and the Powertrain Control Module (PCM).

2.	Look for any chafed, pierced, pinched, or partially broken wires.

3.	Look for broken, bent, pushed out or corroded terminals.

4.	Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.

5.	Look for the data to change or for the DTC to reset during the wiggle test.

6.	Perform any Technical Service Bulletins that may apply.

Were any problems found?

Yes

Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

P2123-ACCELERATOR PEDAL POSITION SENSOR 1 CIRCUIT HIGH

POSSIBLE CAUSES