P2127-ACCELERATOR PEDAL POSITION SENSOR 2 CIRCUIT LOW

For a complete wiring diagram Refer to Section 8W

When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
Set Condition:
The PCM detects that the APP Sensor 2 input voltage is below the minimum acceptable value.

Possible Causes

INTERMITTENT DTC

(K858) 5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND

(K29) APP SIGNAL 2 CIRCUIT SHORTED TO GROUND

(K858) 5 VOLT SUPPLY CIRCUIT SHORTED TO (K400) SENSOR GROUND CIRCUIT

(K858) 5 VOLT SUPPLY CIRCUIT SHORTED TO (K167) SENSOR GROUND CIRCUIT

(K29) APP SIGNAL 2 CIRCUIT SHORTED TO (K400) SENSOR GROUND CIRCUIT

(K29) APP SIGNAL 2 CIRCUIT SHORTED TO (K167) SENSOR GROUND CIRCUIT

(K858) 5 VOLT SUPPLY CIRCUIT OPEN OR HIGH RESISTANCE

(K29) APP SIGNAL 2 CIRCUIT OPEN OR HIGH RESISTANCE

ACCELERATOR PEDAL POSITION SENSOR

POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Diagnostic Test

1. DTC IS ACTIVE

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

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 can result in personal injury or death.

With the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

Go to 2

Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

2. (K858) 5 VOLT SUPPLY CIRCUIT VOLTAGE

Turn the ignition off.
Disconnect the Accelerator Pedal Position Sensor connector.
Turn the ignition on.
Measure the voltage of the (K858) 5 Volt Supply circuit in the Accelerator Pedal Position Sensor harness connector.

Is the voltage above 4.5 volts?

Yes

Go to 6

Go to 3

3. (K858) 5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND

Turn the ignition on.
Disconnect the Powertrain Control Module (PCM) connector.
Measure the resistance between ground and the (K858) 5 Volt Supply circuit in the Accelerator Pedal Position Sensor harness connector.

Is the resistance above 1000 ohms?

Yes

Go to 4

Repair the (K858) 5 Volt Supply circuit for a short to ground.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

4. (K858) 5 VOLT SUPPLY CIRCUIT SHORTED TO (K400) SENSOR GROUND CIRCUIT

Measure the resistance between the (K858) 5 Volt Supply circuit and the (K400) Sensor Ground circuit in the Accelerator Pedal Position Sensor harness connector.

Is the resistance above 100 ohms?

Yes

Go to 5

Repair the (K858) 5 Volt Supply circuit for a short to the (K400) Sensor Ground circuit.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

5. (K858) 5 VOLT SUPPLY CIRCUIT SHORTED TO (K167) SENSOR GROUND CIRCUIT

Measure the resistance between the (K858) 5 Volt Supply circuit and the (K167) Sensor Ground circuit in the Accelerator Pedal Position Sensor harness connector.

Is the resistance above 100 ohms?

Yes

Go to 6

Repair the (K858) 5 Volt Supply circuit for a short to the (K167) Sensor Ground circuit.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

6. (K858) 5 VOLT SUPPLY CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (K858) 5 Volt Supply circuit between the Accelerator Pedal Position Sensor harness connector and the Powertrain Control Module (PCM) harness connector.

Is the resistance below 5.0 ohms?

Yes

Go to 7

Repair the (K858) 5 Volt Supply circuit for an open circuit or high resistance.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

7. (K29) APP SIGNAL 2 CIRCUIT SHORTED TO GROUND

Turn the ignition off.
Disconnect the Powertrain Control Module (PCM) connector.
Measure the resistance between ground and the (K29) APP Signal 2 circuit in the Accelerator Pedal Position Sensor harness connector.

Is the resistance above 100 ohms?

Yes

Go to 8

Repair the (K29) APP Signal 2 circuit for a short to ground.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

8. (K29) APP SIGNAL 2 CIRCUIT SHORTED TO (K400) SENSOR GROUND CIRCUIT

Measure the resistance between the (K29) APP Signal 2 circuit and the (K400) Sensor Ground circuit in the Accelerator Pedal Position Sensor harness connector.

Is the resistance above 100 ohms?

Yes

Go to 9

Repair the (K29) APP Signal 2 circuit for a short to the (K400) Sensor Ground circuit.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

9. (K29) APP SIGNAL 2 CIRCUIT SHORTED TO (K167) SENSOR GROUND CIRCUIT

Measure the resistance between the (K29) APP Signal 2 circuit and the (K167) Sensor Ground circuit in the Accelerator Pedal Position Sensor harness connector.

Is the resistance above 100 ohms?

Yes

Go to 10

Repair the (K29) APP Signal 2 circuit for a short to the (K167) Sensor Ground circuit.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

10. (K29) APP SIGNAL 2 CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (K29) APP Signal 2 circuit between the Accelerator Pedal Position Sensor harness connector and the Powertrain Control Module (PCM) harness connector.

Is the resistance below 5.0 ohms?

Yes

Go to 11

Repair the (K29) APP Signal 2 circuit for an open circuit or high resistance.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

11. ACCELERATOR PEDAL POSITION SENSOR

Turn the ignition off.
Connect the Powertrain Control Module (PCM) connector.
Connect a jumper wire between the (K858) 5 Volt Supply circuit and the (K29) APP Signal 2 circuit in the Accelerator Pedal Position Sensor harness connector.
Turn the ignition on.
With the scan tool, read the Accelerator Pedal Position Sensor signal voltage.

Is the voltage above 4.5 volts with the jumper wire in place?

Yes

Replace the Accelerator Pedal Position Sensor in accordance with the Service Information.

Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Go to 12

12. POWERTRAIN CONTROL MODULE (PCM)

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).
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

Repair as necessary.

Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).