A/C - Musty Odors On Hot/Humid Days
TSB SB06-12-S002Musty Odor From HVAC System
ISSUE DATE: MAY 2006
Affected Vehicles
2003-2006 Isuzu Ascender (US) with Automatic Temperature Control HVAC System (RPO CJ2)
Service Information
Condition:
Some customers may comment on a musty odor from the heating, ventilation and air conditioning (HVAC) system. This condition occurs most often on initial start up after the vehicle was driven on a hot humid day.
Possible Cause:
This condition may be caused by condensation build-up on the evaporator core, which does not evaporate by itself in high humidity conditions.
Correction:
Reflash HVAC Control Module to enable after blow function.
Service Procedure
Technicians are to reprogram the HVAC Control Module with an updated software calibration that will enable the after blow function.
The new calibration will be released beginning with IDS Version 7 or newer. As always, make sure your TECH2 is updated with the latest software version. The blower motor will turn on approximately 10 minutes after the vehicle is shut off. The blower motor will run continuously for 10 minutes at a 30% duty cycle. The after blow function will only activate if the air conditioning compressor was engaged during conditions of high ambient temperature. If the vehicle is started within 10 minutes of the last key off, the after blow function from the previous key cycle will be cancelled.
IMPORTANT:
Technicians should not attempt to reflash a vehicle with a Manual Temperature Control HVAC system (RPO CJ3).
Vehicles being delivered in areas prone to high humidity conditions would benefit from having the after blow enable calibration installed at delivery prior to allowing any initial condensate build-up conditions to occur.
Warranty Claim Information
Use the labor operation shown.
NOTE:
1. Labor Time includes administrative time allowance.
2. Information released on paper and electronic format prior to bulletin release cannot be updated. For the most current and up to date information refer to the website.
3. Always refer to the Isuzu Service Policy Procedure Manual for specific details on warranty coverage and policies.
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