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
2Original wording in English
HYUNDAI
Reported code forms P2135
HYUNDAI: DTC P2135/P0638 OR COLD ENGINE RPM FLUCTUATION; TPS REPLACEMENT AND ECM UPDATE. SOME 2.7L, 3.3L OR 3.8L ENGINES IN MODELS IDENTIFIED IN THE APPLICABILITY LIST MAY EXPERIENCE ONE OR MORE OF THE CONDITIONS…
HYUNDAI
Reported code forms P2135
HYUNDAI: ECM UPDATE: 2009 GENESIS DTC P2135 LOGIC IMPROVEMENT. TO IMPROVE THE DTC P2135 THROTTLE POSITION SENSORS 1/2 VOLTAGE CORRELATION DIAGNOSTIC LOGIC ON SOME VEHICLES SOFTWARE UPDATE. *PE
Check vehicle applicability
2A 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.