GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using the diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Battery Positive Voltage Circuits

1

1

--

--

Ignition Voltage Circuits

1

1

--

--

Keyword 2000 Serial Data

1

1

1

--

Module Ground Circuits

--

1

--

--

1. Scan tool does not communicate with keyword 2000 device

Circuit/System Description

The climate control seat module (CCSM) communicates with a scan tool via the keyword 2000 serial data circuit. The keyword 2000 system is for diagnostics of the CCSM only. There is no communication between any other modules on the keyword 2000 serial data system.

Diagnostic Aids

Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.

Reference Information

Schematic Reference

    •  Heated/Cooled Seat Schematics
    •  Data Communication Schematics

Connector End View Reference

Heated/Cooled Seat Connector End Views

Description and Operation

Data Link Communications Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Circuit/System Testing

  1. Ignition OFF, disconnect all of the harness connectors of the CCSM.
  2. Test for less than 1 ohm of resistance between the module ground circuit and ground.
  3. If greater than 1 ohm, repair the ground circuit for an open/high resistance.
  4. Ignition ON, verify that a test lamp illuminates between the battery positive voltage circuit and ground.
  5. If the test lamp does not illuminate, repair the circuit for a short to ground or an open/high resistance. If the circuit fuse is open, also test the positive voltage outputs of the module for a short to ground. If the circuits test normal, replace the CCSM.
  6. Verify that a test lamp illuminates between the ignition voltage circuits and ground.
  7. If the test lamp does not illuminate, repair the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit fuse is open, also test the positive voltage outputs of the module for a short to ground. If the circuits test normal, replace the CCSM.
  8. Test for infinite resistance between the data link connector (DLC) keyword 2000 serial data circuit and ground.
  9. If less than the specified value, test the serial data circuit for a short to ground.
  10. Test for less than 1 volt between the DLC keyword 2000 serial data circuit and ground.
  11. If greater than the specified range, test the serial data circuit for a short to voltage.
  12. Test for less than 1 ohm of resistance in the keyword 2000 serial data circuit between the CCSM and the DLC.
  13. If greater than the specified range, test the serial data circuit for open/high resistance.
  14. If all circuits test normal, replace CCSM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for CCSM replacement, setup, and programming