Powertrain Management (LUW, ECM)
DTC P0641, P0651, P0697, or P06A3 (LUW, ECM)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC P0641
- 5V Reference 1 Circuit
DTC P0651
- 5V Reference 2 Circuit
DTC P0697
- 5V Reference 3 Circuit
DTC P06A3
- 5V Reference 4 Circuit
Circuit/System Description
The engine control module (ECM) has four 5 V reference circuits. The ECM provides the 5 V reference to various sensors. A short to ground or voltage on one of the 5 V reference circuits will affect all components connected to that 5 V reference circuit. The ECM monitors the voltage on the 5 V reference circuits.
Conditions for Running the DTC
DTCs P0641, P0651, P0697, and P06A3 run continuously when the ignition voltage is greater than 6.4 V.
Conditions for Setting the DTC
The ECM detects a voltage out of tolerance condition on the 5 V reference 1, 2, 3, or 4 circuit for greater than 0.2 s.
Action Taken When the DTC Sets
DTCs P0641, P0651, P0697, and P06A3 are Type A DTCs.
Conditions for Clearing the DTC
DTCs P0641, P0651, P0697, and P06A3 are Type A DTCs.
Diagnostic Aids
* If a shared 5 V reference circuit is shorted to ground or shorted to a voltage, other 5 V reference circuits may be affected.
* The scan tool 5 V reference parameter should display between 4.8-5.2 V.
P0641
The 5 V reference 1 circuit provides 5 V to the following sensors:
* The exhaust camshaft position sensor
* The intake camshaft position sensor
* The A/C refrigerant pressure sensor
* The fuel tank pressure sensor
P0651
The 5 V reference 2 circuit provides 5 V to the following sensors:
* The clutch pedal position (CPP) sensor
* The crankshaft position sensor
* The brake pedal position sensor
P0697
The 5 V reference 3 circuit provides 5 V to the following sensors:
* The accelerator pedal position (APP) sensor 2
* The manifold absolute pressure (MAP) sensor
P06A3
The 5 V reference 4 circuit provides 5 V to the following sensors:
* The accelerator pedal position (APP) sensor 1
* The throttle body throttle position sensors 1
* The throttle body throttle position sensor 2
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON, observe the DTC information with a scan tool. DTCs P0641, P0651, P0697, and P06A3 should not set.
2. Engine idling, observe the following circuit status parameters:
* 5 V Reference 1 Circuit Status
* 5 V Reference 2 Circuit Status
* 5 V Reference 3 Circuit Status
* 5 V Reference 4 Circuit Status
Each parameter should display OK.
3. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
Circuit/System Testing
Note: Additional DTCs will set when disconnecting components.
1. Vehicle OFF, disconnect the harness connector at all appropriate sensors for the applicable DTC. Refer to Diagnostic Aids.
2. Ignition ON, test for 4.8-5.2 V between one of the affected 5 V reference circuits and ground.
• If the voltage is less than the specified range, test for a short to ground on the 5 V reference circuit for each affected component. If all circuits test normal, replace the K20 Engine Control Module.
• If the voltage is greater than the specified range, test for a short to voltage on the 5 V reference circuit for each affected component. If all circuits test normal, replace the K20 Engine Control Module.
Note: A short to voltage on the signal circuit of certain components may cause this DTC to set.
3. Connect each component associated with the affected 5 V reference circuit one at a time while monitoring the appropriate scan tool 5 V Reference 1, 2, 3, or 4 Voltage parameter. Verify the voltage remains 4.8-5.2 V.
• If not within the specified range when a component is connected, test the signal circuit of that component for a short to voltage. If the circuit tests normal, replace the component.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Accelerator Pedal Position Sensor Replacement Service and Repair
* Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement (LDE/LUW) Service and RepairAir Conditioning (A/C) Refrigerant Pressure Sensor Replacement (LUV)
* Brake Pedal Position Sensor Replacement
* Camshaft Position Sensor Replacement Service and Repair
* Clutch Pedal Position Sensor Replacement Service and Repair
* Crankshaft Position Sensor Replacement Service and Repair
* Manifold Absolute Pressure Sensor Replacement Service and Repair
* Throttle Body Assembly Replacement Removal and Replacement
* Control Module References Control Module References for replacement, programming, and setup.