P2135

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

Throttle / pedal position Generic OBD-II Medium

What it means

P2135 means the two internal throttle position sensor signals ('A' and 'B') no longer agree with each other. The ECM uses this redundancy as a safety check, so when the voltages disagree it usually forces the engine into reduced-power or limp mode. It most often points to a failing throttle body sensor or a wiring/connector fault.

Medium

Can I keep driving? Often limited — a correlation fault usually forces reduced-power/limp mode; drivable at low speed but full throttle response may be unavailable until repaired.

Real-world scan data

Seen in

2,189

scans in the past year

Found in

0.3%

of scans

0.6%

of scans that found faults

Appears alongside · share of P2135 scans

P0420in 32.1% of scans

P2119in 31.9% of scans

P0300in 28.5% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Reduced engine power / limp mode
Surging or unstable idle
Hesitation or poor throttle response
Occasionally stalling or a hard start

Common causes

Most likely first

Faulty throttle position sensor / throttle body (the two internal signals disagree)Likely
Open, shorted, or chafed sensor harness wiringCommon
Poor or corroded connection at the throttle body connectorCommon
Faulty ECM/PCMLess often

How to diagnose & fix

Work through it in order

Read freeze-frame and note the two TPS voltages to see which signal is off.
Inspect the throttle body connector and harness for corrosion, bent pins, or chafing.
With key on, confirm both sensor signals sweep smoothly and track each other as the throttle moves.
Check the 5-volt reference and ground shared by both sensors.
If the wiring is good but the signals still disagree, replace the throttle body / TPS and relearn idle, then retest.

FAQ

Quick answers

Is it safe to drive with P2135?+

Only cautiously. The car usually drops into reduced-power mode and can stall, so it is best to repair it promptly rather than drive far.

Can I just clear P2135?+

It returns quickly — the ECM constantly compares the two throttle-sensor signals, so it re-sets until the sensor or wiring is fixed.

Read & clear P2135 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX