P06D4 - Sensor Reference Voltage 5 Circuit High

Theory of Operation

This sensor supply circuit provides a 5-Volt supply to the Accelerator Pedal Position 2 Sensor (APPS), Diesel Particulate Filter Pressure Sensor, Soot Delta Pressure Sensor, and the Transmission Pressure Sensor. The Powertrain Control Module (PCM) illuminates the MIL lamp immediately after the diagnostic runs and fails. The ETC lamp will also flash. During this time the customer will be in a limp home mode. The PCM will turn off the MIL lamp after the diagnostic runs and passes in four consecutive drive cycles.

When Monitored:

While the engine is running.

Set Condition:

Voltage detected on the 5-Volt Supply circuit is above a calibrated value.

Possible Causes

5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
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).

Diagnostic Test

1. ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, record all Freeze frame data.
3. With the scan tool, erase DTCs.
4. Turn the ignition off for 75 seconds.
5. Turn the ignition on.
6. With the scan tool, read DTCs.
Did the DTC reset?

Yes
• Go To 2

No
• Perform the INTERMITTENT CONDITION diagnostic procedure. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

2. CHECK THE (F856) 5-VOLT SUPPLY FOR A SHORT TO VOLTAGE

1. Turn the ignition off.
2. Disconnect the components listed in the theory of operation.
3. Turn the ignition on.
4. Measure the voltage of the (F856) 5-Volt Supply circuit at the Accelerator Pedal Position harness connector.
Is the voltage reading above 5.1 Volts?

Yes
• Repair the (F856) 5-Volt Supply circuit for a short to voltage.
• Perform the POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

No
• Go To 3

3. CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT

1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
NOTE: Check connectors - Clean/repair as necessary.
3. Measure the resistance between the (F856) 5-Volt Supply circuit and all other circuits in the PCM C2 connector.
Is the resistance below 10k Ohms between the (F856) 5-Volt Supply circuit and any of the circuits?

Yes

• Repair the short between the (F856) 5-Volt Supply circuit and the circuit that measured below 10k Ohms.
• Perform the POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

No
• Replace the Powertrain Control Module in accordance with the service information.
• Perform the POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).