GM Service Manual Online
For 1990-2009 cars only

Object Number: 413323  Size: MF
ABS Components
Cell 44: Power, Ground, and ANTILOCK Indicator
Cell 10: Battery
Handling ESD Sensitive Parts Notice
Cell 50: Power, Ground, and Class 2
Cell 50: Power, Ground, and Class 2 (Export)

Circuit Description

The PCM monitors various parameters and will not allow traction control operation if any parameter falls outside a specified range.

Conditions for Setting the DTC

The PCM detects a malfunction and causes TCS shut down until the malfunction has been corrected.

Action Taken When the DTC Sets

    • A malfunction DTC is stored (This is a temporary malfunction).
    • TCS is disabled.
    • The TRACTION CONTROL indicator is turned ON.
    • If TCS is no longer inhibited, the TRACTION CONTROL indicator will be turned OFF, but the DTC will be stored as history.

Conditions for Clearing the DTC

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

Diagnostic Aids

This DTC is for information only. As an aid to the technician, this DTC indicates that there are no problems in the ABS/TCS system.

Test Description

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

  1. This step tests if DTC C1278 resets.

DTC C1278 TCS Temporarily Inhibited By PCM

Step

Action

Value(s)

Yes

No

1

Was the on 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.

Are any other DTCs set?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

Is DTC C1278 set as a current code?

--

Go to Step 5

Go to Step 4

4

  1. Start the engine and test drive the vehicle at least 16 km/h (10 mph) while monitoring the scan tool for ABS/TCS DTCs.
  2. Repeat the above drive cycle sequence 2 more times.

Did DTC C1278 set in the last 3 drive cycles?

--

Go to Step  5

Go to Diagnostic System Check

5

Perform the Powertrain OBD System Check. Refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls-4.6L.

Did the vehicle pass the OBD System Check?

--

Go to Diagnostic Aids

Go to Powertrain On Board Diagnostic (OBD) System Check