P2135 means Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation. An electronic throttle body has two position sensors that should always agree. The computer has seen their signals disagree. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P2135 means
Most vehicles built in the last two decades use electronic throttle control instead of a throttle cable: the accelerator pedal carries two or three position sensors, and the throttle body has a motor and two position sensors of its own. The computer compares the redundant sensors constantly, and any disagreement triggers reduced-power mode as a safety measure. Older engines with a throttle cable control idle with a separate idle air control valve.
P2135 symptoms
- Reduced-power mode, often with a wrench or throttle warning light
- Poor acceleration or no throttle response
- Stalling
Common causes of P2135
- Worn sensor track inside the throttle body
- Corroded or loose connector at the throttle body
- Damaged wiring
- Rarely, an engine computer fault
How to diagnose P2135
- Inspect and clean the throttle body connector
- Compare both sensor readings on a scan tool while opening the throttle
- Wiggle-test the harness while watching the readings
- Replace the throttle body if the sensors disagree with good wiring
Can you drive with P2135?
Limited: reduced power can make merging and passing unsafe. Repair promptly.
P2135 tips
On many electronic throttle bodies the two position sensors are built in, so the fix is a new throttle body when the wiring tests good. After replacement, run the throttle relearn procedure if your vehicle requires one, or the idle may be unstable.
Will P2135 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P2135 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0121 | Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance |
| P2101 | Throttle Actuator Control Motor Circuit Range/Performance |
| P2138 | Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation |
Guides that help
When it is more than a sensor
Throttle and idle codes are fixed at the throttle body, the pedal, a sensor or a leak. If those check out and the engine still runs poorly, a compression test separates a control problem from a worn engine; compare engines by code on our engines page.
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