Circuit Description
Traction Control is simultaneously controlled by the EBTCM and the PCM. The PCM sends a DELIVERED TORQUE message via a Pulse Width Modulated (PWM) signal to the EBTCM confirming the delivered torque level for proper Traction Control system operation. The EBTCM supplies the pull up voltage.
Conditions for Setting the DTC
DTC C1276 can be set anytime when ignition voltage is present. A malfunction exists if the PWM signal is out of range or no signal is received for a period of 7 seconds.
Action Taken When the DTC Sets
A malfunction DTC is stored, the TCS is disabled and the Traction Control indicator is turned ON. The ABS remains functional.
Conditions for Clearing the DTC
| • | Condition for DTC is no longer present and scan tool clear DTC function is used. |
| • | Fifty ignition cycles have passed with no DTC(s) detected. |
Diagnostic Aids
| • | It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction. |
| • | If an intermittent malfunction exists refer to General Electrical Diagnosis in Wiring Systems. |
| • | Possible causes for DTC C1276 to set:: |
| - | Open in CKT 464. |
| - | CKT 464 shorted to ground or voltage. |
| - | Communication frequency problem. |
| - | Communication duty cycle problem. |
| - | CKT 464 has a wiring problem, terminal corrosion, or poor connections. |
| - | EBTCM not receiving information from the PCM. |
Test Description
The numbers below refer to step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Diagnostic System Check | |
2 | Check the following grounds, G402 and G106 making sure each ground is clean, tight and free of damage. Refer to Master Electrical Component List in Wiring Systems. Were any loose, damaged, or corroded grounds found? | -- | ||
3 | Repair ground as necessary. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
Is the duty cycle within the range specified in the value(s) column? | 5 - 25% | |||
Using J 39200 DMM, measure the DC Hz between J 39700 terminals 6 and B. Is the frequency within the range specified in the value(s) column? | 121 - 134Hz | |||
6 | Replace the EBTCM. Refer to Electronic Brake and Traction Control Module . Is the replacement complete? | -- | Go to Diagnostic System Check | -- |
7 |
Is the voltage within the range specified in the value(s) column? | Battery Volts | ||
8 |
Is the voltage within the range specified in the value(s) column? | Greater than 1V | ||
9 | Repair CKT 464 for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
10 |
Is the resistance within the range specified in the value(s) column? | OL (infinite) | ||
11 | Repair CKT 464 for a short to ground. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
12 |
Is the resistance within the range specified in the value(s) column? | 0 - 2ohms | ||
13 | Replace PCM. Refer to Powertrain Control Module/Throttle Actuator Control Module Replacement in Engine Controls. Is the Replacement complete? | -- | Go to Diagnostic System Check | -- |
14 | Repair CKT 464 for an open. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
