P0653

P0653-SENSOR REFERENCE VOLTAGE 2 HIGH

For a complete wiring diagram Refer to Diagrams/Electrical.

Theory of Operation


This sensor supply circuit provides a 5 volt supply to: 1. Engine position sensor 2. Intake manifold temperature/pressure sensor 3. Exhaust pressure sensor 4. Fuel pressure sensor 5. Ambient temperature/pressure sensor 6. EGR valve 7. Fan clutch assembly 8. Crankcase pressure sensor A MIL lamp will be lit immediately after this diagnostic runs and fails. The MIL lamp will turn off once the diagnostic runs and passes in 4 consecutive drive cycles.

- When Monitored:
While the engine is running.

- Set Condition:
Voltage detected on the sensor supply is above a calibrated value.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview


Diagnostic Test


1. ECM
Turn the ignition off.
Disconnect the ECM 60 pin harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Turn the ignition on.
Measure the voltage between the Sensor (F855) #1 5-volt Supply and the Sensor #1 Return pin at the ECM.
Is the voltage between 4.5 and 5.5 volts?

Yes


- Go To 2


No


- Replace and program the ECM.
- Perform POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test



2. (F855) 5-VOLT SUPPLY SHORTED TO VOLTAGE
Key off.
Disconnect the sensor connectors for each pressure sensor, and the engine position sensor.
Disconnect the ECM 50 way harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Ignition on, engine off.
Measure the voltage between the supply circuit at each pressure sensor harness connector and battery negative.
Measure voltage between the (F855) 5-volt supply circuit at the engine position sensor harness connector and battery negative.
Is the voltage less than 1 volt?

Yes


- Go To 3


No


- Repair the (F855) 5-volt supply shorted to voltage.
- Perform POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test



3. SENSOR SUPPLY SHORTED TO VOLTAGE IN HARNESS
Measure the resistance between the #1 sensor supply circuit and all other circuit in the ECM connectors.
Is the resistance less than 10 ohms?

Yes


- Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Intermittent Condition


No


- Repair the harness shorted to voltage.
- Perform POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test