GM Service Manual Online
For 1990-2009 cars only

Object Number: 397530  Size: LF
ABS Components
Cell 44: Indicator and Stoplamp/BTSI Switch
Cell 110: Stop Lamps
Cell 110: Stop Lamps
Handling ESD Sensitive Parts Notice
Cell 10: Battery Power Circuits to Fuse Blocks (2 of 2)
Cell 34: Stoplamp Switch

Circuit Description

This DTC is the second portion of DTC C1291. If DTC C1291 occurred during the last ignition cycle, DTC C1293 becomes a current malfunction during the next ignition cycle. This keeps the TCS disabled until a stoplamp switch ON state is detected. When a stoplamp switch ON state is detected during an ignition cycle in which DTC C1293 is a current malfunction, DTC C1293 will become a history DTC at the end of the current ignition cycle, and the TCS will enable at the start of the next ignition cycle. DTC C1293 alone indicates that DTC C1291 occurred previously, but is intermittent, or has been corrected.

Conditions for Setting the DTC

A DTC C1291 was set in a previous ignition cycle.

Action Taken When the DTC Sets

    • A DTC C1293 is stored
    • The TCS is disabled
    • The TRACTION OFF indicator is turned on
    • The ABS remains functional

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present and you used the scan tool Clear DTC function.
    • The EBCM/EBTCM does not detect the DTC in 50 drive cycles.

Diagnostic Aids

    • Thoroughly inspect the wiring and the connectors. Failure to carefully and fully inspect the wiring and the connectors can result in misdiagnosis. Misdiagnosis may cause replacement of parts without repairing the malfunction.
    • The following conditions may cause most intermittent malfunctions:
       - Poor connections
       - Rubbed through wire insulation
       - A broken wire inside the insulation
    • Verify proper stoplamp/BTSI switch operation during the Data List of the scan tool. As the brake is applied, the data list should display the stoplamp/BTSI switch applied within an inch of travel.
    • If an intermittent malfunction exists, refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step checks for the proper duty cycle.

DTC C1293 Code C1291 Set In Previous Ignition Cycle

Step

Action

Value(s)

Yes

No

1

Was the ABS Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check

2

  1. Turn the ignition switch to the RUN position with the engine off.
  2. Using a scan tool, read the ABS/TCS DTCs.

Is DTC C1291 set as a history or current code?

--

Go to DTC C1291 Open Brake Lamp Switch Contacts During Deceleration

Go to Diagnostic System Check