What does this code mean?
In the cited Ford and GM applications, the two throttle-position signals do not agree within the calibrated relationship. This can trigger reduced engine power. It does not mean the throttle is simply dirty, or that every vehicle needs an entire throttle body; signal naming and repair strategy must be checked for the exact application.
Sources and interpretation [1]
A code identifies a detected condition, not a part that must automatically be replaced.
Before replacing a part
Save current/history status and compare both position signals with the correct diagnostic procedure. Match engine RPO and bulletin applicability before parts selection. With reduced power or unreliable acceleration, follow the owner's guidance and arrange service rather than attempting a full-throttle test.
Manufacturer communications
6Original wording in English
CADILLAC, CHEVROLET, GMC, HUMMER
Reported code forms P2135
This technical bulletin provides a procedure for replacing the throttle position sensor cover for concerns regarding a indicator lamp illuminated reduced power message displayed and DTC P2135 set.
CADILLAC, CHEVROLET, GMC, HUMMER
Reported code forms P2135
This technical bulletin provides a procedure for replacing the throttle position sensor cover for concerns regarding a indicator lamp illuminated reduced power message displayed and DTC P2135 set.
CADILLAC, CHEVROLET, GMC, HUMMER
Reported code forms P2135
Diagnosis and Repair - Malfunction Indicator Lamp (MIL) Illuminated, Reduced Engine Power Message Displayed, DTC P2135 Set
CADILLAC, CHEVROLET, GMC, HUMMER
Reported code forms P2135
GM: DIAGNOSIS AND REPAIR- MALFUNCTION INDICATOR LAMP ILLUMINATED, REDUCE ENGINE POWER MESSAGE DISPLAYED, DTC P2135 SET. ALSO INCLUDED MODEL SIERRA DENALI YEAR 2010-2011 *JS
CADILLAC, CHEVROLET, GMC, HUMMER
Reported code forms P2135
THIS BULLETIN IS BEING ISSUED TO REVISE STEP 4 OF DIAGNOSTIC TROUBLE CODE (DTC) P2135. *TT
BUICK, CADILLAC, CHEVROLET, GMC, HUMMER, PONTIAC
Reported code forms P2135
SERVICE ENGINE SOON LIGHT AND REDUCED ENGINE POWER WITH A DIAGNOSTIC TROUBLE CODE P1516. DIAGNOSTIC TROUBLE CODES P0120, P0220, P1514, P1515, P1518 AND P2135 MAY ALSO BE PRESENT. *TT
Check vehicle applicability
9A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
Sources and interpretation
These explanations are editorial summaries of the linked manufacturer material. PDF page numbers count from the first file page. Original publications are in English; translations are reference aids. A cited edition is not a claim that it is the manufacturer's latest instruction.
- 2024–2025 MY OBD System Operation Summary for Gasoline Engines ↗
Ford Motor Company · PDF page(s) 99 ·
- 11-06-04-007C · Reduced engine power, P2135 ↗
General Motors · PDF page(s) 1 ·
Source check date · 2026-10-27
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.