CJ2 HVAC DTCs B0361 And B0441 And Drivers Side AC Blows Warm - keywords PIINSI I000694 accumulator air automatic compressor condensor condition control display evaporator head HVAC inoperative

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

CJ2 may experience an HVAC control head that will not properly control air mix doors after a battery disconnect. The vehicle may have a temperature difference side to side and may set DTCs B0361 and/or B0441. A typical complaint may be that the right side cools down, but the left side is warm.

Air Mix Door build variance or wear may cause a slight over travel condition of the door. The HVAC control module will perform a recalibration of the actuators during certain conditions including a battery disconnect. During recalibration, the HVAC control module will drive the actuators to their minimum and maximum travel extremes (0 and 255 counts). The module issues a travel command to 0 (& 255) counts, but expects to see feedback above 0 as the door hits the cold stop in the case. The module will then calculate a travel range from this data and compare it to a calibrated range within the HVAC control module. If the actual travel range is not within the calibrated expected range the actuator will be considered not calibrated, the DTC will set and the failure action will prevent full cold range travel of the actuator.

An actual range sticking between 10-245 counts suggests an obstruction (something stuck in the door limiting its travel). An actual range under 5 or over 250 (at respective ends) suggests an over travel condition (wear, damaged foam seals, etc.).

If thorough diagnosis of the electrical system shows all electrical components to be ok, replacement of the HVAC control module with a 2001 or newer part number is required for 1997 to 2000 model years.

If this has already been done (or the car is 2001 and newer), a reset/re-time of the actuator's internal feedback sensor to lag slightly behind the actual position can be performed. Open the actuator case and reset the output gear to sensor gear by 1 tooth. This will allow a feedback change of about 4 counts when performing end limit learn. Current service actuators can not be retimed. The current type actuator can be identified by a "snap together" housing VS a housing that has both halves joined by screws. A "screw together" service part is available using P/N 89018539.

Install P/N 89018539 and command the actuator to its end limits. This may require use of an external command signal to achieve true full travel. Use a test lamp connected to ground and back probe actuator command signal at pin 6. This pulls the signal low and causes the actuator to move one direction. Allow the actuator to move to full travel and note the feedback counts on the Tech 2. Then connect the test lamp to B+ and again probe the pin 6 signal. This raises the command voltage and drives the actuator the opposite direction. Allow full travel and note the count value.

In cases of left temp door DTCs a common true feedback is 0 counts at one end and approximately 245 on the other end. If so, then resetting the actuator by one tooth should help. In some cases retiming by two teeth is required.

To retime an actuator first remove it and place the actuator on a level work surface. Remove all housing screws and then CAREFULLY separate the halves. Be sure to not disturb the timing when performing this step. With the outer cover removed the internal components are accessible. There are two idler/reduction gears between the motor and the output gear. There is a separate gear driven feedback actuator meshed to the output gear away from the idler gears.

Important:  Use a Sharpie pen to identify the original gear teeth position between the output gear and the feedback sensor gear for reference (idler gear position is not relevant).

Then lift the output gear and move it relative to the feedback sensor gear, hold the sensor gear steady and relocate the output gear counterclockwise by 1 tooth. Reassemble the idler gears and housing and reinstall the actuator in the car. Retest end limits as described above. If low end counts are now above 0, and high end is less than 255, the position should resolve all DTCs. If counts still are not high enough on the low end then remove the actuator and retime by one additional tooth as needed.

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.