A/C - Control Incorrectly Displays DTC's
NUMBER: 24-008-04GROUP: Heating & Air Conditioning
DATE: December 18, 2004
SUBJECT:
DTC's Are Incorrectly Displayed By Manual Temperature Control Module
OVERVIEW:
This bulletin discusses the incorrect display of the climate control diagnostic trouble codes by the Manual Temperature Control (MTC) module.
MODELS:
2005 (WK) Grand Cherokee
NOTE:
This bulletin applies to vehicle equipped with a Manual Temperature Control (sales code HAA) built prior to November 28, 2004 (MDH 1128XX).
DISCUSSION:
The Manual Temperature Control (MTC) module, on some early built vehicles, may have software that will display the wrong numeric value for a diagnostic trouble code (DTC). The MTC is not connected to the CAN bus and is not addressable with a scan tool. The MTC module DTC's must be obtained by manually manipulating the MTC front controls (see Entering Display DTC Mode - MTC System in the 2005 Grand Cherokee Technical Information available on TechCONNECT). Each numeric value for the respective DTC is displayed by the MTC by flashing the NC mode switch LED.
The MTC will display, via the A/C mode switch LED, a numeric code that will consist of two digits. The numeric code will have a tens digit and it will have a ones digit. The ones digit is incorrectly displayed. As an example: a true DTC 47 - Recirc Door Bound will be incorrectly displayed by the MTC module as a A6" fault code, or the MTC module will incorrectly display a '2" fault code when the true fault is a DTC 21 - Blend Door Range Too Large.
This condition will occur with MTC modules having part number 55111009AF.
NOTE:
MTC modules are not to be replaced because of this condition. Use the table to properly identify any DTC's displayed in the MTC for the subject vehicles.
The table shows both the incorrectly displayed DTC numeric value along with the corresponding correct DTC value that is published in the service information in TechCONNECT and its description:
POLICY:
Information Only
Disclaimer:
This bulletin is supplied as technical information only and is not an authorization for repair.