Subject: | (HYBRID) ABS And Brake Lamp and Multiple DTC's |
Models: | 2008 Chevrolet Tahoe Hybrid |
| with Two-Mode Hybrid System (RPO HP2) |
| On vehicles built before VIN Break 9R112133 |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
ABS Lamp and a Service Brake System message in the Drivers Information Center (DIC) with one of the following scenario.
- DTC's C0277, C0278, C0161, C129C, C129F, and C12B1 set together
- DTC's C0110.61 and C12E8 set together.
Recommendation/Instructions:
If you experience a vehicle with one of the concerns listed above, please record all DTCs and sub codes. The sub codes can be obtained by using the following path with the Tech2: EBCM / DTC / Additional DTC Information / Enhanced DTC data. Then clear codes
in all modules.
- After recording all DTCs and sub codes on the repair order, monitor the master cylinder pressure sensor parameter in the EBCM data list with foot off the brake. The reading should be at zero, but may rapidly flicker +/- 15 PSI (+/- 100 kpa) which
is normal. Any other readings are considered abnormal and you should check the master cylinder pressure sensor or circuits.
- After the master cylinder pressure sensor is reading correctly, Program the EBCM and the ECM with the latest calibrations listed in TIS-2-Web by selecting EBCM/HCP/ECM/TCM/BECM Sequential Programming.
Note: It is
essential that the Multiple Diagnostic Interface (MDI) and the TIS terminal are equipped with the latest software before performing (SPS). Due to the time requirements of programming a controller, it is recommended that an external power source be used to maintain
system voltage. Stable battery voltage is critical during programming. Any fluctuation, spiking, over voltage or loss of voltage will interrupt programming. To ensure trouble-free programming, GM recommends using one of the following external power sources:
• | A Midtronic PCS charger. |
• | Battery voltage must be maintained above 12 volts during the entire reprogramming event or programming may be interrupted. The programming event will take approximately 45 minutes to complete. |
- After performing the EBCM/HCP/ECM/TCM/BECM Sequential Programming, please perform the following.
- Perform EBCM relearn which the Tech 2 scan tool.
- Start and drive vehicle up to 20 mph and stop
- Shut the key off for 1 minute,
- Clear codes in all modules
- Drive vehicle again
- Confirm codes do not return
Note: The only way DTC: C0561 can be cleared on a Hybrid Equipped Vehicle is to cycle the ignition off, start the vehicle and clear the DTC while the vehicle is running, or after the ignition is cycled off and on again.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.