The two throttle/pedal sensors don't agree.
P2135 — also written P2135, P 2135, 2135 — is the OBD-II code for throttle/pedal position sensor a/b correlation. Same code, same fix: this page covers every spelling of it.
This is your car's brain getting two different stories from the sensors that control the throttle—it gets confused and puts you in limp mode for safety. It’s extremely common on Vauxhall petrols and Ford Duratec engines.
P2135 is a fuel & air fault code, typically costing £90–£500 to put right in a UK garage.
What P2135 actually feels like to drive
- Car goes into 'Limp Mode' with the 'Service ESP' or spanner light on.
- The engine won't rev past 2,000 or 2,500 RPM no matter how hard you floor it.
- The throttle feels 'dead' or unresponsive at roundabouts (proper dangerous).
- Jerking or surging while trying to maintain a steady 30mph.
- Sudden loss of power that resets temporarily if you cycle the ignition.
What causes P2135?
- Failed accelerator pedal sensor
- Failed throttle body position sensors
- Wiring fault
UK vehicles that throw P2135 most often
- Vauxhall Corsa D/E 1.2 & 1.4 (A12XER/A14XER) 2007-2015
- Vauxhall Astra J 1.4 Turbo (A14NET) 2010-2015
- Ford Focus Mk2 1.6 & 1.8 Duratec 2005-2011
- Ford Fiesta Mk6 1.25/1.4 Zetec 2008-2012
- Nissan Qashqai J10 1.6 Petrol 2007-2013
- Peugeot 207 1.4 VTi (EP3) 2007-2012
How P2135 is fixed
- Replace pedal position sensor
- Replace throttle body
The P2135 misdiagnosis that wastes money
I see so many lads jumping straight to the throttle body, or worse, just spraying half a tin of carb cleaner down the throat and hoping for the best. Usually, it's the pedal assembly itself or a 'green' connector at the ECU. On the Vauxhall Corsas and Astras, I’ve seen moisture get into the plug and corrode the pins. If you just swap the throttle body without checking the wiring harness or the pedal sensor readings on live data, you're just throwing £200 of the customer's money in the bin for nothing.
What a UK garage should charge for P2135
For a diagnostic plug-in, expect to pay £50-£80 at an indie. If it’s just the pedal sensor, a Bosch or Hella unit is usually £80-£120 plus an hour’s labour (£60-£90). If it’s the throttle body, you’re looking at £200-£350 for a quality VDO or Pierburg part. Main dealers will easily double these prices, often quoting £600+ for a job that takes me 40 minutes. Avoid the cheap £40 eBay throttle bodies; they usually fail within a month and trigger the same code.
P2135 repair cost in the UK
Most P2135 repairs land between £90–£500 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Bob's tip on P2135
Before you let a garage sell you a new throttle body, ask them: 'Did you check the correlation on the live data graph?' If the two signals don't mirror each other perfectly when you sweep the pedal, that's your smoking gun. Also, if you’ve got a Vauxhall, insist they check the pins at the ECU for corrosion first. A proper tech should be using an oscilloscope or at least a decent scan tool to see those two voltages moving together. If they just read the code and start quoting for parts, walk away.
Can you drive with P2135?
Limp mode.
Urgency: high.