Powertrain, generic (extended)

P2135 Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2135 compares the two position tracks of the electronic throttle, A and B, and sets when they no longer describe the same plate angle. GM's 2006-2007 tables allow a 7 % offset at closed throttle rising to 10 % at full opening and count failures every 12.5 ms until 19 of 39 have failed. Ford flags more than 7 degrees of disagreement; its 2012 and 2020-2023 summaries show only the wrench lamp, the 2024 summary also the MIL. Mitsubishi lists P2135 for the 2022 Outlander as a one-trip MIL code. Nissan bulletin NTB21-080 cures P2135 on the 2020-2021 Frontier without driveability complaints by ECM reprogramming. Mercedes traced it on AMG M177 V8s to high resistance in the throttle actuator pins. The ECU then limits throttle opening.

Likely causes

Worn or contaminated position tracks in the throttle body
Raised contact resistance or corrosion at the throttle connector
ECM calibration prone to false detection (update available on some models)
Fault on the shared 5 V reference or ground of both tracks

Symptoms

  • Engine warning lamp or wrench lamp on
  • Reduced engine power, limited throttle opening
  • Rough or raised idle

Repair estimate

DifficultyMediumDIY possible
Parts and labour€0–700
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

What to check first

  1. Inspect throttle body connector
  2. Compare both signals on a scan tool
  3. Replace throttle body if signals disagree

Parts involved

throttle position sensorthrottle body

Related codes

P2136P2137P0121P0221P0122P0222

References: gsi.ext.gm.com, fordservicecontent.com, static.nhtsa.gov, static.nhtsa.gov.