OBD codes / P2135
P2135
SeriousThrottle/Pedal Position Sensor A/B Voltage Correlation
Take P2135 seriously. It typically forces reduced-power mode, sharply limiting acceleration — which can be unsafe pulling into traffic or onto a highway. Drive gently and briefly to a shop if you must, but get it diagnosed before relying on the car.
What this code means
Electronic throttle and pedal assemblies carry two position sensors ('A' and 'B') that should always agree. P2135 sets when the two disagree beyond a safe margin — the computer no longer trusts the throttle reading. The most common cause is a failing throttle position sensor or throttle body (where both sensors live), but a corroded connector or wiring fault that shifts one signal can do it too. For safety the computer usually drops the engine into reduced-power 'limp' mode until it's resolved.
Symptoms you might notice
- Reduced-power or 'limp' mode (limited acceleration)
- Throttle that feels dead, sluggish, or erratic
- Stalling or rough idle
- Check-engine light, often with a warning light
What it costs to fix
Typical range: $50–$600 · about ~0.3–1.5 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Connector / wiring repair | $10–$120 | ~0.5–1.5 hrs |
| Accelerator pedal position sensor | $50–$250 | ~0.3–1 hrs |
| Electronic throttle body | $150–$500 | ~0.5–1.5 hrs |
Always check connectors first — a corroded or loose connector is a cheap, common cause of two sensors disagreeing. If the sensors themselves are at fault, the pedal sensor is usually cheaper than the throttle body.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P2135 for my exact vehicle →
Frequently asked
Can I drive with P2135?
Cautiously and only a short distance. It usually triggers reduced-power mode, so acceleration is sharply limited — dangerous when merging or crossing traffic. Get it diagnosed promptly rather than driving on it.
What does 'voltage correlation' mean for P2135?
The throttle/pedal system has two sensors that should always read in agreement. P2135 means their voltages no longer correlate — they disagree — so the computer can't trust the throttle position and limits power for safety.
What usually causes P2135?
A failing throttle position sensor or throttle body is common, but a corroded connector or a wiring fault that shifts one sensor's signal is a frequent, cheaper cause. Checking the connectors first can save replacing parts.
How much does it cost to fix P2135?
From a cheap connector/wiring repair to a pedal sensor or a full electronic throttle body. Diagnosis (and checking connectors first) determines which, so you don't replace a good throttle body.
Seeing P2135 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P2135 for my vehicleGeneric OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.