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Home >> Chevrolet >> 2009 >> Cobalt L4-2.0L Turbo >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0699

P0699




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

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

DTC Descriptors
DTC P0641
- 5-Volt Reference 1 Circuit

DTC P0642
- 5-Volt Reference 1 Low Voltage

DTC P0643
- 5-Volt Reference 1 High Voltage

DTC P0651
- 5-Volt Reference 2 Circuit

DTC P0652
- 5-Volt Reference 2 Low Voltage

DTC P0653
- 5-Volt Reference 2 High Voltage

DTC P0697
- 5-Volt Reference 3 Circuit

DTC P0698
- 5-Volt Reference 3 Low Voltage

DTC P0699
- 5-Volt Reference 3 High Voltage

Diagnostic Fault Information





Circuit/System Description

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

The 5-volt reference 1 bus provides 5 volts to the following sensors:

* The manifold absolute pressure (MAP) sensor
* The clutch apply sensor
* The fuel rail sensor
* The fuel tank pressure (FTP) sensor
* The intake air pressure and temperature sensor

The 5-volt reference 2 bus provides 5 volts to the following sensors:

* The accelerator pedal position (APP) sensor 1
* The exhaust camshaft position (CMP) sensor
* The intake camshaft position (CMP) sensor

The 5-volt reference 3 bus provides 5 volts to the following sensors:

* The APP sensor 2
* The crankshaft position (CKP) sensor
* The air conditioning (A/C) refrigerant pressure sensor
* The throttle position (TP) sensor 1 and 2
* The brake booster vacuum sensor

Conditions for Running the DTC

* DTCs P0601, P0602, P0603, P0604, and P0606 are not set.
* The ignition is in Run, or Crank.
* The ignition voltage is more than 5.23 volts.
* 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-volt reference 1, 2 or 3 bus for more than 3 seconds.

P0642, P0652, and P0698

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

P0643, P0653, and P0699

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

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

* It may be possible to locate the fault by disconnecting one component at a time from the 5-volt reference circuit while viewing the 5-Volt 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-volt 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 (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

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

Circuit/System Testing

Important: Additional DTCs will set when disconnecting the components.


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

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


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

• If the voltage is less than the specified range, test for a short to ground on all the 5-volt reference circuits. If all circuits test normal, replace the ECM.
• If the voltage is greater than the specified range, test for a short to voltage on all the 5-volt reference circuits. If all circuits test normal, replace the ECM.

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 1 volt.

• If the voltage display increases greater than the specified value when a component is connected, test the signal circuit for a short to voltage. If all circuits test normal, replace the ECM.
• If the voltage display decreases more than the specified value when a component is connected, replace the component.

Repair Instructions

* Accelerator Pedal Position Sensor Replacement (Service and Repair)
* Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement (Service and Repair)
* Crankshaft Position Sensor Replacement (Service and Repair)
* Camshaft Position Sensor Replacement - Exhaust (Service and Repair)
* Camshaft Position Sensor Replacement - Intake (Service and Repair)
* Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement (Service and Repair)
* Fuel Tank Pressure Sensor Replacement (Service and Repair)
* Intake Air Pressure and Temperature Sensor Replacement (Service and Repair)
* Manifold Absolute Pressure Sensor Replacement (Service and Repair)
* Throttle Body Assembly Replacement (Removal and Replacement)
* Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions) for ECM replacement, setup, and programming.

Repair Verification

With the ignition ON and the engine OFF, observe the 5-Volt Reference 1, 2 and 3 parameters. The scan tool should display 5-volt reference circuit status OK for a normally operating system.

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