Mechanics

CHEVY PROBLEM

2005 Chevrolet Tahoe • V8 4WD Automatic • 2,200 miles

2005 chevy tahoe with air cond. Running cold air on drivers side hot on pass. Side?
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Buzzster9
August 3, 2011.




A common concern, that usually ends up being a faulty actuator. Remove the HVAC/ECAS fuse from the underhood fuse block for 10 seconds or so. Install the fuse, turn the key on without touching any controls for a minute or so. See if the function resumes to normal. There is also a reprogramming that can be done to address this concern. It is in a GM service bulletin, included below.

#06-01-38-003: Intermittent Ticking Noise from I/P, Poor A/C Performance, HVAC DTCs B0229, B0414, B0424, B3770, (Reprogram HVAC Control Module) - (Apr 27, 2006)

Subject: Intermittent Ticking Noise from I/P, Poor A/C Performance, HVAC DTCs B0229, B0414, B0424, B3770 (Reprogram HVAC Control Module)

Models: 2004-2006 Cadillac Escalade Models

2004-2006 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2004-2006 GMC Sierra Models, Yukon Models

with Air Conditioning (RPOs CJ2, CJ3)

Condition

Some customers may comment on one or more of the following concerns: Intermittent ticking/clicking noise from the instrument panel.

Recirculation mode does not work or Air Conditioning (A/C) system performance is poor during high ambient temperatures.

Unable to control the driver side temperature.

Unable to control the passenger side temperature.

Unable to change the front system modes.

Cause

This condition may be caused by the Heating, Ventilation and Air Conditioning (HVAC) actuators that may hunt for the correct commanded position. This cycling may cause a clicking or ticking noise.

An overtravel of the HVAC system control doors may cause one or more of the concerns listed above. If an overtravel occurs, a Diagnostic Trouble Code (DTC) will be set, and the door will go to a preset default position. When a system door defaults, that door will stay at the default position until the DTC is cleared. After the DTC is cleared, the door will operate properly until the overtravel condition re-occurs.

The following table lists the HVAC system doors and the DTC associated with it.

System Door

Overtravel DTC

Air inlet door (recirculation door)

B0229

Left temperature door

B0414

Right temperature door

B0424

Front system mode door

B3770

Correction

Technicians are to perform the normal diagnostic procedures in SI for these concerns. If diagnostics show that the HVAC system door(s) travel below 5 counts (out of the lower range) or above 250 counts (out of the upper range), then update the software calibrations in the HVAC control module. The new calibrations were made available to dealerships as part of TIS2000 incremental satellite update version 2.5, which was broadcast to dealers in February 2006.

The new calibrations have been updated to compensate for the actuator overtravel condition, the actuator hunting and the ticking/clicking noises. The new calibrations effectively eliminate the codes listed above, the default position of the doors associated with the DTCs and opens up the feedback position value. The new calibrations should not be used unless the vehicle has one or more of the customer concerns listed above or a DTC listed above has been set. The new calibrations will not correct any other DTC or A/C system performance concern.

Factoryjack
Aug 3, 2011.


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