P2135: Throttle/Pedal Position Sensor Voltage Correlation
Two throttle position signals disagree, so the computer cannot trust what the throttle is doing.
Severity: 3 of 4
Park it and arrange repair. This code often triggers reduced power mode, and an unpredictable throttle can make merging or passing dangerous. Have it towed or drive only a short slow distance if you must.
Estimate range covers the repairs listed below; see the cost breakdown. A flashing check engine light, a hot temperature gauge, or brakes that feel different mean stop driving and get help.
What P2135 means
Modern cars use electronic throttle control. The throttle body has two position sensors, and the computer compares them. If they disagree, it sets P2135 and often limits engine power for safety.
This is a safety system. Do not ignore it.
Two separate sensors inside the throttle body report the throttle plate angle. They are designed to move in a fixed relationship, so the computer can catch a fault. When the two signals stop matching, the computer cannot know the true throttle position and limits power to stay safe.
Similar sensors exist in the accelerator pedal. Some vehicles share a reference voltage between the pedal and throttle sensors, so a short in one can upset the other.
Intermittent P2135 faults often come from connectors with corrosion or from wiring that rubs against engine parts and breaks only when the engine moves.
Common causes (cheapest likely first)
- Corroded or loose throttle body connector. Check and clean first.
- Damaged wiring. Chafed harness.
- Failing throttle body sensor. Usually replaced as a throttle body assembly.
- Accelerator pedal sensor. Some vehicles share the circuit.
Symptoms
- Reduced power mode
- Erratic acceleration
- Stalling
- Warning light
- Car stuck at low speed or idle
- Engine idles but will not rev
DIY difficulty: Moderate
Connector cleaning is easy. Throttle body replacement may require a relearn procedure with a scan tool.
Tools: OBD-II scanner, Multimeter, Electrical contact cleaner
Safe diagnosis steps
- Turn the engine off before touching any throttle body parts. The throttle plate can snap shut with force.
- Inspect the connector for green corrosion, bent pins, and loose locks.
- Wiggle test the harness while watching live data, if your scanner shows both sensor signals.
- Measure reference and ground with a multimeter before buying a throttle body.
Estimated repair cost
This is an estimate, built from typical parts price ranges plus labor hours times an assumed shop rate of $110 to $190 per hour. Actual prices vary by vehicle, region, and shop. Diagnosis fees are often extra.
| Repair | Parts | Labor | Estimate (low / high) |
|---|---|---|---|
| Connector repair | $5 to $40 | 0.3 to 1.0 h | $5 + 0.3 × $110 = $38 $40 + 1.0 × $190 = $230 |
| Throttle body | $150 to $600 | 0.5 to 1.5 h | $150 + 0.5 × $110 = $205 $600 + 1.5 × $190 = $885 |
| Accelerator pedal sensor | $80 to $300 | 0.5 to 1.0 h | $80 + 0.5 × $110 = $135 $300 + 1.0 × $190 = $490 |
Watch a repair video
Search YouTube for “P2135 fix” videos. Pick a recent video that matches your engine, and confirm the diagnosis before buying parts.
P2135 by make
Brand specific notes: Nissan. Other makes: the code works the same way; see all makes.
Repair manuals
Step-by-step service manuals with torque specs and wiring diagrams:
Haynes manuals Chilton manuals
Affiliate disclosure: links in this box may earn FixOrPark a commission at no extra cost to you.
Related codes
Check for recalls
Before paying for a repair, enter your VIN in the NHTSA recall lookup. Emissions parts may also be covered by a federal emissions warranty; check your warranty booklet.
FAQ
Is P2135 dangerous?
It can be, because power can drop unexpectedly.
Can cleaning the throttle body fix it?
Rarely. It is an electrical correlation problem, not dirt.
Can a weak battery cause P2135?
Low voltage can cause odd electrical codes. Test the battery and charging system, but do not assume it is the cause.
Does the throttle body need programming after replacement?
Many vehicles need a relearn procedure. Some do it automatically; others need a scan tool. Check the service information for your vehicle.