P0651

DTC P0651

DTC DESCRIPTORS

DTC P0641
5-volt Reference 1 Circuit

DTC P0651
5-volt Reference 2 Circuit

DIAGNOSTIC FAULT INFORMATION




Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

CIRCUIT/SYSTEM DESCRIPTION
The engine control module (ECM) has 2 5-volt reference circuits. The ECM provides the 5-volt reference to various sensors. Each reference circuit provides a 5-volt reference for more than one sensor. A short to ground or voltage on one of the 5-volt reference circuits will affect all components connected to that 5-volt reference circuit. The ECM monitors the voltage on the 5-volt reference circuits.

CONDITIONS FOR RUNNING THE DTC
- The ignition is ON.
- DTCs P0641 and P0651 run continuously when the above condition is met.

CONDITIONS FOR SETTING THE DTC
The control module detects a voltage above 5.5 volts, or below 4.5 volts, on either 5-volt reference circuit for more than 0.5 second.

ACTION TAKEN WHEN THE DTC SETS
DTCs P0641 and P0651 are Type B DTCs.

CONDITIONS FOR CLEARING THE DTC
DTCs P0641 and P0651 are Type B DTCs.

DIAGNOSTIC AIDS

P0641
The 5-volt reference 1 circuit provides 5 volts to the following sensors:
- The accelerator pedal position (APP) sensor 1
- The throttle position (TP) sensor 1
- The TP sensor 2

P0651
The 5-volt reference 2 circuit provides 5 volts to the following sensors:
- The APP sensor 2
- The air conditioning (A/C) refrigerant pressure sensor
- The exhaust gas recirculation (EGR) valve
- The fuel tank pressure (FTP) sensor
- The intake manifold tuning (IMT) valve position sensor
- The manifold absolute pressure (MAP) sensor
- The rough road sensor

CIRCUIT/SYSTEM VERIFICATION
1. Ignition ON, observe the DTC information with a scan tool. DTCs P0641 and P0651 should not set.
2. If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List.

CIRCUIT/SYSTEM TESTING
1. Ignition OFF, disconnect the harness connector of all appropriate sensors for the applicable DTC. Refer to Diagnostic Aids.

IMPORTANT: Additional DTCs will set when disconnecting the components.

2. Ignition ON, measure for 4.6-5.4 volts between one of the 5-volt reference circuits and ground.
- If the voltage is less than 4.6 volts, test for a short to ground on all the 5-volt reference circuits. If all circuits test normal, replace the control module.

IMPORTANT: A short to voltage on the signal circuit of certain components may cause this DTC to set.

- If the voltage is greater than 5.4 volts, test for a short to voltage on all the 5-volt reference circuits, or the signal circuit, for each component associated with the appropriate 5-volt reference circuit. If all circuits test normal, replace the control module.

3. Connect each component associated with the 5-volt reference circuit one at a time while monitoring the voltage. The voltage should not change more than 0.5 volt.

- If the voltage display changes more than the specified value when a component is connected, replace the component.

REPAIR INSTRUCTIONS
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests