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DTC P0641-P0643, P0651-P0653, or P0697-P0699

DTC P0641-P0643, P0651-P0653, or P0697-P0699

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 Descriptors

DTC P0641

5 V Reference 1 Circuit

DTC P0642

5 V Reference 1 Low Voltage

DTC P0643

5 V Reference 1 High Voltage

DTC P0651

5 V Reference 2 Circuit

DTC P0652

5 V Reference 2 Low Voltage

DTC P0653

5 V Reference 2 High Voltage

DTC P0697

5 V Reference 3 Circuit

DTC P0698

5 V Reference 3 Low Voltage

DTC P0699

5 V Reference 3 High Voltage

Circuit/System Description

The engine control module (ECM) has 3 internal 5 V reference busses called 5 V reference 1, 5 V reference 2, and 5 V reference 3. Each reference bus provides 5 V reference circuits for more than one sensor. Therefore, a fault condition on one 5 V reference circuit will affect the other 5 V reference circuits connected to that reference bus. The ECM monitors the voltage on the 5 V reference busses.

Conditions for Running the DTC


DTCs P0602, P0603, P0604, and P0606 are not set.

The ignition is in Run, or Crank.

The ignition voltage is more than 5.23 V.

DTCs P0641, P0642, P0643, P0651, P0652, P0653, P0697, P0698, and P0699 run continuously when the above conditions are met.


Conditions for Setting the DTC

P0641, P0651, and P0697

These DTCs set when the ECM detects a voltage out of tolerance condition on the 5 V reference 1, 2 or 3 bus for more than 3 s.

P0642, P0652, and P0698

These DTCs set when the ECM detects a low voltage condition on the 5 V reference 1, 2, or 3 bus for more than 3 s.

P0643, P0653, and P0699

These DTCs set when the ECM detects a high voltage condition on the 5 V reference 1, 2, or 3 bus for more than 3 s.

Action Taken When the DTC Sets

DTCs P0641, P0642, P0643, P0651, P0652, P0653, P0697, P0698, and P0699 are Type A DTCs.

Conditions for Clearing the DTC

DTCs P0641, P0642, P0643, P0651, P0652, P0653, P0697, P0698, and P0699 are Type A DTCs.

Diagnostic Aids


The 5 V reference 1 bus provides 5 V to the following sensors:

- B74 manifold absolute pressure (MAP) sensor

- B25B clutch pedal position sensor

- B47B fuel rail sensor

- B65 intake air pressure and temperature sensor

The 5 V reference 2 bus provides 5 V to the following sensors:

- B107 accelerator pedal position (APP) sensor 1

- B23E exhaust camshaft position sensor

- B23F intake camshaft position sensor

The 5 V reference 3 bus provides 5 V to the following sensors:

- B107 APP sensor 2

- B26 crankshaft position sensor

- B1 air conditioning (A/C) refrigerant pressure sensor

- Q38 throttle position sensor 1 and 2

It may be possible to locate the fault by disconnecting one component at a time from the 5 V reference circuit while viewing the 5 V Reference circuit parameter on the scan tool. The scan tool parameter would change from Fault to OK when the source of the fault is disconnected.

If all 5 V reference components have been disconnected and a Fault is still indicated, the fault may exist in the wiring harness.


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

With the ignition ON and the engine OFF, observe the 5 V Reference 1, 5 V Reference 2, and 5 V Reference 3 parameters . The scan tool should display OK for a normally operating system.

Circuit/System Testing


1.
Note

Additional DTCs will set when disconnecting the components.


Ignition OFF, disconnect the harness connector of all appropriate sensors for the applicable DTC.

2.
Note

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


Ignition ON, measure for 4.8-5.2 V between one of the 5 V reference circuits and ground.

3. If the voltage is less than the specified range, test for a short to ground on all the 5 V reference circuits. If all circuits test normal, replace the K20 ECM.

4. If the voltage is greater than the specified range, test for a short to voltage on all the 5 V reference circuits. If all circuits test normal, replace the K20 ECM.

5. Connect each component associated with the 5 V reference circuit, one at a time, while monitoring the voltage. Verify the voltage remains between 4.8-5.2 V.

6. If not within the specified range when a component is connected, test the signal circuit for a short to voltage. If the circuit tests normal, replace the component.


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 (LDK/A20NHT) Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement (Diesel) Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement (LAU/A28NER)

Crankshaft Position Sensor Replacement

Camshaft Position Sensor Replacement - Exhaust

Camshaft Position Sensor Replacement - Intake

Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement

Intake Air Pressure and Temperature Sensor Replacement

Manifold Absolute Pressure Sensor Replacement

Throttle Body Assembly Replacement

Control Module References for ECM replacement, setup, and programming.