A/C - Poor Cooling Performance
NUMBER: 24-003-12GROUP: Heating & Air Conditioning
DATE: October 30, 2012
HELP USING THE wiTECH DIAGNOSTIC APPLICATION FOR FLASHING AN ECU IS
AVAILABLE BY SELECTING "HELP" THEN "HELP CONTENTS" AT THE TOP OF
THE wiTECH DIAGNOSTIC APPLICATION WINDOW.
THE wiTECH SOFTWARE LEVEL MUST BE AT RELEASE 13.02 OR HIGHER TO PERFORM THIS PROCEDURE.
SUBJECT:
Poor A/C Performance
OVERVIEW:
This bulletin involves flash reprogramming the Manual Temperature Control Module (MTC).
MODELS:
2011 - 2012 (WK) Grand Cherokee
NOTE:
This bulletin applies to all vehicles equipped with Air Conditioning with Dual Zone Temperature Control (Sales Code HAD).
SYMPTOM/CONDITION:
The customers may experience poor A/C performance in 60°F (16°C) - 90°F (32°C) ambient temperature. This may result in little to no A/C operation or reduced airflow from the instrument panel vents. This condition often occurs after a extended drive cycle (greater that 2 hours) with the A/C on and the blower speed is set to the low position. Once
the vehicle is shut off or the A/C is turned off for approximately 2 hours the A/C will operate normally.
DIAGNOSIS:
Using a Scan Tool (wiTECH) with the appropriate Diagnostic Procedures available in TechCONNECT, verify all other A/C functions operate as designed. If DTC's are present record them on the repair order and repair as necessary before proceeding further with this bulletin.
If the above condition is present, perform the Repair Procedure.
REPAIR PROCEDURE:
NOTE:
Install a battery charger to ensure battery voltage does not drop below 13.2 volts. Do not allow the charging voltage to climb above 13.5 volts during the flash process.
NOTE:If this flash process is interrupted/aborted, the flash should be restarted.
1. Using the wiTECH Diagnostic Application for flashing a MTC is made available through the wiTECH Diagnostic Application. For instructions select the "HELP" tab on upper portion of the wiTECH window, then "HELP CONTENTS." This will open the Welcome to wiTECH Help screen were help topics can be selected.
2. After MTC reprogramming, the following must be performed:Clear any DTC's that may have been set in other modules due to reprogramming. The wiTECH application will automatically present all DTCs after the flash and allow the tech to clear them.
3. Cycle the ignition switch.
POLICY:
Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
FAILURE CODE:
Disclaimer:
This bulletin is supplied as technical information only and is not an authorization for repair.