MIL On, DTC 121 (Replace HVAC Programmer) Set

File in Section: 6E - Engine Fuel & Emission

Bulletin No.: 63-65-33

Date: May, 1996

Subject:
Malfunction Indicator Lamp ("Service Engine Soon" Light) Comes On in Rapid
Ambient Temperature Change, DTC 121 will Set (Replace HVAC Programmer)

Model:
1995 Oldsmobile Aurora
with 4.0L Engine (VIN C - RPO L47)

Condition

Some owners may comment that the Malfunction Indicator Lamp ("Service Engine Soon" light) comes on during a rapid ambient temperature change (from a moderate to cold ambient temperature). Also, Diagnostic Trouble Code (DTC) 121, A/C high side temperature sensor circuit, will set. No other DTC's will be set. In certain ambient temperatures, the HVAC Programmer will set a "false" DTC 121.

Correction

Follow the diagnosis for DTC 121 in Section 6E3-A of the Service Manual to ensure that a "legitimate" DTC 121 is not set. If no other DTC's are set, replace the HVAC programmer with P/N 16222233.

Parts Information

Parts are currently available from GMSPO.

Warranty Information

For vehicles repaired under warranty, use:

Labor
Operation Description Labor Time
Use published
Programmer, A/C - labor operation
D0780 Replace time