Short answer
P2135 sets when the two throttle position signals (A and B) disagree; OBD-Codes.com says it sets when they deviate for two seconds. Expect reduced power, stalling or a throttle that holds one RPM. Common causes: corroded or bent connector terminals, a damaged pigtail, a failed electronic throttle body (or a warped cover), a failed accelerator pedal sensor or its wiring, or a needed relearn.
- Code
- P2135
- Generic title
- Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation
- Meaning
- The two sensors in an electronic throttle body disagree.
- Severity
- High (reduced power is common)
What P2135 means
OBD-Codes.com describes the throttle body as containing two embedded throttle position sensors whose voltages the computer compares. When the two signals agree, everything runs normally; when they deviate for two seconds, P2135 sets. The code title includes the pedal (Throttle/Pedal Position Sensor/Switch A/B), and the pedal sensor and its wiring are on the cause list too.
Symptoms
- Stalling when coming to a stop
- Loss of power or no acceleration
- Sudden power loss at cruise
- Throttle stuck at the current RPM
- Check engine light
Causes
P2135 causes, per OBD-Codes.com
| Cause | How to check |
|---|---|
| Corroded or bent terminals in the throttle body connector | Unplug and inspect the pins |
| Bare pigtail wire shorting to ground | Inspect the pigtail; replace it if damaged |
| Distorted throttle body cover | Look for cracks or warping |
| Faulty electronic throttle body | Live data shows A and B drifting apart |
| Accelerator pedal sensor or wiring | Pedal signal should rise smoothly as you press |
| Sensors need a relearn or reprogramming | Relearn per service manual or dealer |
| Engine computer | Last, after everything above |
How to diagnose P2135
Check service bulletins
Start with technical service bulletins for your vehicle; known fixes are common for this code.
Fix related codes first
Address codes such as P2136 or pedal sensor codes, since they may be the direct cause.
Inspect the connector
Look for damaged or missing terminals and corrosion. Clean, apply dielectric grease, and reconnect, or replace the pigtail.
Inspect the throttle body
Check the top cover for cracks or warping. If damaged, replace the throttle body, or the cover where it is sold separately.
Test the pedal sensor
Watch the pedal signal while pressing the pedal slowly. It should rise smoothly with no spikes.
Relearn
Run the relearn for your vehicle, or have the computer reprogrammed at a dealer if needed.
More: TPS vs throttle body, replacement cost, and the codes hub.
Questions people ask
Is P2135 dangerous?
It can be. OBD-Codes.com lists sudden power loss at cruise and a throttle stuck at the current RPM among the symptoms. Pull over safely if power drops, and do not drive it far until it is fixed.
Do I need a whole throttle body for P2135?
Often, because the sensors are built into the throttle body. But connector faults and pedal sensors cause the same code, and some applications have sensor-only parts. Inspect and test first.
Why did my car go into limp mode with P2135?
When the computer cannot trust the throttle position, it limits power so the throttle cannot open further than it should. That reduced power mode is a safety feature, not a separate fault.
Can a dirty throttle body cause P2135?
OBD-Codes.com lists a distorted throttle body cover that stops the gears turning properly among the causes. Heavy carbon is a separate issue; follow your maker’s cleaning guidance and never force the plate on an electronic throttle.
Sources
Last reviewed 2026-10-12. General guidance only: specs, procedures and fitment vary by vehicle, so confirm in your service manual and on the listing before you buy or wrench.