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Service Engine Soon Light And DTC P1125 P2101 P2120 P2125 Or P2138 - keywords 3.8 body hesitation L26 MIL mode PCM power reduced SES throttle

Subject:Service Engine Soon Light And DTC P1125 P2101 P2120 P2125 Or P2138

Models:2008 Buick Lucerne, LaCrosse/Allure
2008 Pontiac Grand Prix
Equipped with 3.8L L26 Engine



This PI was superseded to update the DTC list to include P2120. Please discard PIP4343.


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

Condition/Concern:

Some customers may comment that the Service Engine Soon light is illuminated. In addition some may also comment that the vehicle was exhibiting a hesitation and/or had the "reduced power mode" symbol or message displayed. When checking for diagnostic Trouble Codes (DTC) in the Powertrain Control Module (PCM), codes P1125, P2120, P2125 or P2138 may be found.

Recommendation/Instructions:

Metro Detroit Dealers:

Engineering is looking for a vehicle in the "Metro Detroit" (Southeast Michigan) area that exhibits the described condition. Dealers in the "Metro Detroit" area that have such a vehicle should contact Jim Kelly at (586) 492-5612 BEFORE PERFORMING ANY DIAGNOSIS, DISASSEMBLY OR REPLACEMENT OF PARTS. He will assist in making arrangements for Engineering to review the vehicle at your Metro Detroit area location.

Also before calling him, using a Tech 2, please make sure you have captured and saved the data that the PCM took when the DTC set. Do NOT contact him if you have already disassembled, replaced any parts or have not captured and saved the data.

All Other Dealers:

Follow the diagnostic information in SI. If your diagnosis leads you to replacing the throttle body assembly, then contact Jim Kelly at (586) 492-5612. He will obtain the necessary information from you and will give you information on where to mail the old throttle body assembly to.

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.