GM Service Manual Online
For 1990-2009 cars only

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 P0649 01: Cruise Engaged Indicator Control Circuit Shorted to Voltage

DTC P0649 02: Cruise Engaged Indicator Control Circuit Shorted to Ground

DTC P0649 04: Cruise Engaged Indicator Control Circuit Open

DTC P0649 54: Cruise Engaged Indicator Control Circuit High Temperature

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Cruise Engaged Lamp Voltage Supply

P0649 04

P0649 04

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Cruise Engaged Indicator Control

P0649 02

P0649 04

P0649 01

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Circuit/System Description

The cruise engaged indicator, is located on the instrument panel cluster (IPC). Ignition 1 voltage is supplied directly to the cruise engaged indicator. The engine control module (ECM) turns the cruise engaged indicator ON by grounding the control circuit.

Conditions for Running the DTC

    • The engine is operating.
    • The ignition 1 voltage is between 7.5-16 volts.
    • The DTCs run continuously once the above conditions are met.

Conditions for Setting the DTC

The ECM detects the cruise engaged indicator control circuit is open or shorted to ground or voltage.

Action Taken When the DTC Sets

DTC P0649 is a Type C DTC.

Conditions for Clearing the DTC

DTC P0649 is a Type C DTC.

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. Engine idling, command the cruise indicator ON and OFF with a scan tool. The indicator should turn ON and OFF.
  2. Observe the DTC information with a scan tool. DTC P0649 should not set.
  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

  1. If any other indicators are inoperative on the P16 instrument panel cluster (IPC), refer to Symptoms - Displays and Gages.
  2. Ignition OFF, disconnect the harness connector at the K20 ECM.
  3. Ignition ON, the cruise engage indicator should not illuminate.
  4. If the cruise engage indicator illuminates, test the control circuit for a short to ground. If the circuit test normal, replace the P16 IPC.
  5. Ignition ON, connect a 3 A fused jumper wire between the cruise engage indicator control circuit terminal and ground. The cruise engage indicator should illuminate.
  6. If the cruise engage indicator does not illuminate, test the control circuit for a short to voltage or an open/high resistance. If the circuit test normal, replace the P16 IPC.
    If the cruise engage indicator illuminates, inspect for a poor connection or replace the K20 ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Instrument Cluster Replacement
    •  Control Module References for ECM replacement, setup, and programming