For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptor

DTC P0641 00: 5 Volt Reference 1 Circuit
DTC P0651 00: 5 Volt Reference 2 Circuit
DTC P0697 00: 5 Volt Reference 3 Circuit
DTC P06A3 00: 5 Volt Reference 4 Circuit

### Circuit/System Description

The engine control module (ECM) has 4 5-volt reference circuits. The ECM provides the 5-volt reference to various sensors. 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.

• | The ECM is not commanding reduced engine power.

• | The ignition voltage is greater than 6 V.

• | The DTCs run continuously when the above conditions are met.

### Conditions for Setting the DTC

The ECM detects the 5-volt reference is out of range for less than 1 s.

### Action Taken When the DTC Sets

• | DTCs P0641 00, and P0651 00, are Type B DTCs.

• | DTC P0696 00, and P06A3 00 are Type C DTCs.

### Conditions for Clearing the DTC

• | DTCs P0641 00, and P0651 00, are Type B DTCs.

• | DTC P0696 00, and P06A3 00 are Type C DTCs.

### Diagnostic Aids

• | If a shared 5-volt reference circuit is shorted to ground or shorted to a voltage, other 5-volt reference circuits may be affected.

• | The scan tool 5-volt reference parameter should display between 4.8-5.2 V.

#### P0641

The 5-volt reference 1 circuit provides 5 V to the following sensors:

• | The camshaft position actuator solenoid valve - exhaust sensor

• | The camshaft position actuator solenoid valve - intake sensor

• | The A/C refrigerant pressure sensor air

• | The vehicle speed (VSS) sensor

• | The fuel tank pressure sensor fuel tank pressure sensor

#### P0651

The 5-volt reference 2 circuit provides 5 V to the following sensors:

• | The clutch pedal position (CPP) sensor

• | The crankshaft position sensor

#### P0697

The 5-volt 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-volt 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

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Ignition ON, observe the DTC information with a scan tool. DTCs P0641 00, P0651 00, P0697 00, and P06A3 00 should not set.
2. Engine idling, observe the following circuit status parameters:

• | 5 Volt Reference 1 Circuit Status

• | 5 Volt Reference 2 Circuit Status

• | 5 Volt Reference 3 Circuit Status

• | 5 Volt 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. Ignition 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 each of the 5-volt reference circuits listed below and ground:

• | Q6F Camshaft Position (CMP) Actuator Solenoid Valve - Intake pin 1

• | Q6E Camshaft Position (CMP) Actuator Solenoid Valve - Exhaust pin 1

• | B74 Manifold Absolute Pressure (MAP) Sensor pin 1

• | B107 Accelerator Pedal Position (APP) Sensor pin 1

• | B107 Accelerator Pedal Position (APP) Sensor pin 5

• | Q38 Throttle Body pin D and E

• | B26 Crankshaft Position (CKP) Sensor pin 3

• | B14 Manual Transmission Vehicle Speed (VSS) Sensor pin 3

⇒ | If less than the specified range, test for a short to ground on the 5-volt reference circuit. If all circuits test normal, replace the K20 Engine Control Module (ECM).

⇒ | If greater than the specified range, test for a short to voltage on the 5-volt reference circuit. If all circuits test normal, replace the K20 Engine Control Module (ECM).

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 5-volt reference circuit one at a time while monitoring the scan tool 5 volt reference parameter. The voltage should display 5.0 V.

⇒ | If not the specified value, test the signal circuit of the component for a short to voltage. If the circuit tests normal, replace the component. Refer to Diagnostic Aids.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Accelerator Pedal Position Sensor Replacement

• | Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement

• | Manifold Absolute Pressure Sensor Replacement

• | Throttle Body Assembly Replacement

• | Crankshaft Position Sensor Replacement

• | Camshaft Position Sensor Replacement - Intake

• | need LINK for 142097

• | need LINK for Fuel Tank Pressure (FTP) Sensor Replacement

• | Control Module References for replacement, setup, and programming.