Hybrid Two-Mode A/C Blows Warm Air, A/C Compressor Does Not Engage with DTC B101D and U0073 Set (Reprogram ACCM)
| Subject: | Hybrid Two-Mode A/C Blows Warm Air, A/C Compressor Does Not Engage With DTC B101D and U0073 Set (Reprogram ACCM) |
| Models: | 2009 Cadillac Escalade Hybrid |
| 2008-2009 Chevrolet Tahoe Hybrid |
| 2008-2009 GMC Yukon Hybrid |
| with 6.0L Engine (VIN 5 -- RPO LFA) |
| with Automatic Temperature Control HVAC System (RPO CJ2) |
This bulletin is being revised to add the 2009 model year and the 2009 Cadillac Escalade Hybrid. Please discard Corporate Bulletin Number 08-01-39-005 (Section 01 -- HVAC).
Condition
Some customers may comment that the air conditioning (A/C) blows warm air and/or the A/C compressor does not engage.
Upon investigation, the technician may find the following Diagnostic Trouble Codes set :
| • | B101D : ECU Hardware Performance Internal Electronic Failure |
| • | U0073 : Control Module Communication Bus Off |
The A/C compressor will not engage if these codes are set.
Cause
This condition may occur when the underhood battery power is removed from the ACCM. The ACCM software calibration may not retain the current values on power-up.
Correction
Important: Verify that the 12-volt battery has a battery charge of 12 to 16 volts. The battery must be able to maintain a charge during programming. Only use approved Midtronics 165-PCS charger or equivalent to maintain proper battery voltage during programming. The J2534 MDI will reprogram the modules in less time than the Tech 2® scan tool. Clear all DTC codes after programming.
An updated Air Conditioning Compressor Module (ACCM) Calibration is now available to address these concerns. Reprogram the ACCM with the updated software calibration files using the TIS2WEB Service Programming System (SPS) application.
Warranty Information
For vehicles repaired under U.S. warranty, use:
Labor Operation | Description | Labor Time |
|---|---|---|
D9740* | Air Conditioning Compressor Module Programming with SPS | 0.4 hr |
*This labor operation number is for bulletin use only. This number will not be published in the Labor Time Guide. | ||
