Air intakeGeneric OBD-II codeUrgency: Garage soon
Code P2135: throttle or pedal: A/B signals do not match
P2135 means: voltage correlation between throttle or accelerator pedal position sensors or switches "A" and "B".[1][2] The ECU compares the redundant signals from the throttle and accelerator pedal sensors in real time. If they do not agree with each other as they should, it treats it as a safety fault.[1][2]
What code P2135 means
The ECU compares the redundant signals from the throttle and accelerator pedal sensors in real time. If they do not agree with each other as they should, it treats it as a safety fault.[1][2]
It usually forces reduced-power mode: the throttle response drops or disappears and a warning light comes on.[1][2]
Original definition (SAE J2012): Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation[1][2]
Causes of P2135
From most to least likely, according to the sources.
- 1Faulty throttle position sensor, normally built into the throttle body.[1][2][3]
- 2Faulty accelerator pedal position sensor.[1][3]
- 3Damaged, shorted or open wiring, or corroded or loose connectors.[1][2][3]
- 4Degraded 5 V supply or poor earth shared by both signals.[2][3]
- 5ECU problems, such as outdated software, or a faulty connection to the sensors.[1][3]
Symptoms
- Engine warning light on, on many cars together with an electronic throttle warning light.[1][2][3]Engine warning light: faults that cause it
- Reduced-power mode (limp mode).[1][2]Limp mode: faults that cause it
- Loss of power and poor response when accelerating.[1][2][3]Less power: faults that cause it
- Stalling or abrupt engine cut-outs and revs that will not rise.[1][2]Engine stalls: faults that cause it
- Jerking, hesitation and uneven idle.[2][3]Jerking: faults that cause it
How to diagnose P2135
In order: from the most likely and cheapest to check to the most expensive.
- 1Read all the codes and the freeze-frame data. If there are range or circuit codes for a specific sensor, deal with them first.[2]
- 2With a diagnostic tool, plot the throttle's two signals while moving the pedal slowly: they should rise smoothly with a fixed difference between them and without touching.[2]
- 3Inspect the throttle connector and wiring: corroded or loose terminals, moisture, chafed or cut wires.[2][3]
- 4Check the sensor's 5 V supply and earth.[2]
- 5If the sensor is the cause, it is usually replaced together with the complete throttle body. Afterwards, carry out the throttle and pedal relearn the car requires. When cleaning the throttle, do not move it with your fingers: ask an assistant to press the pedal and use a brush.[1][2]
Can I keep driving with P2135?
Garage soon
It is an electronic throttle fault that normally leaves the car in reduced power; the engine may cut out or stall, so it is a real risk in traffic. It should be repaired before you go on using the car normally.[1][2]
Documented faults related to P2135
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
Engine sensors: the most serious faults by engine and car
- High severityFrequency: Occasional2.0 DTI and 2.2 DTIVP44 injection pump and air mass meter failureGerman Wikipedia documents recurring failures of the Bosch VP44 injection pump and the air mass meter in the early years of this engine. An owner testimony for this engine describes the pump being replaced at 192,500 km, at a cost the owner calls «prohibitive».
- Medium severityFrequency: Common2.0 TDIClogged particulate filter or faulty pressure sensorThe 2.0 TDI's particulate filter clogs if the car mostly makes short journeys, because it never gets to regenerate; sometimes the fault is just the differential pressure sensor. Cleaning it costs around €200 and replacing it, €800 to €3,000.Repair (garage): €800–€3,000
- Medium severityFrequency: Common1.4 and 1.6 8vCrankshaft position sensor failure (TDC sensor)The crankshaft position sensor (capteur PMH, or TDC sensor) appears repeatedly in the reliability sources for the Clio II, the Kangoo I and the Dacia Logan I with this engine, with hard cold starting or stalling as the main symptoms. It is a cheap part, but the failure can leave you stranded.
- Medium severityFrequency: Common1.4 and 1.6 16vCrankshaft position sensor failureThe crankshaft position sensor (capteur PMH) appears repeatedly in the reliability sources for almost every generation with this engine, with hard cold starting, stalling or the car cutting out unexpectedly. It is a cheap part, but the failure can leave you stranded.
Accelerator pedal: the most serious faults by engine and car
- High severityFrequency: Rare1.0 VVT-i2010 recall for the accelerator pedalIn January 2010 Toyota recalled, as part of a worldwide campaign, the Aygo, Peugeot 107 and Citroën C1 built between February 2005 and August 2009 because of an accelerator pedal that could stay partly depressed or return slowly to idle.
- Critical severityFrequency: OccasionalMercedes-Benz GLE V167Accelerator pedal mounting plate that bends and releases the pedalThe plate that holds the accelerator pedal module can bend and release the pedal from the body; the pedal can then stay pressed down, prevent kickdown or obstruct the brake pedal. It affected 882 GLE models built between 3 and 17 May 2023.
- High severityFrequency: OccasionalToyota Aygo IAccelerator pedal slow to return on the Toyota Aygo (2010 campaign)In January 2010, Wikipedia records a Toyota recall over the accelerator pedal, which could return slowly to idle; it covered the Aygo, 107 and C1 built between February 2005 and August 2009, although it was later clarified that it only affected the automatic Aygo.
Wiring, connectors and short circuits: the most serious faults by engine and car
- Critical severityFrequency: OccasionalBMW N62 / N63Additional turbo coolant pump with a risk of short circuit and fireIn 2011 BMW recalled 5, 6 and 7 Series, X5 and X6 models built between 2007 and 2011 because of the additional turbo coolant pump: moisture, a short circuit and, in extreme cases, a fire. In 2012 there was another campaign for a crack in the pump, with a more robust version.
- High severityFrequency: Occasional1.3 TCeBlown fuel pump fuseOn the Renault Captur II and Clio V with the 1.3 TCe engine, a 20-amp fuse can blow and leave the car without an engine. According to L'argus, in April 2021 this fault still had no factory fix; the official service centre's diagnosis includes checking, and sometimes replacing, the catalytic converter.
- High severityFrequency: OccasionalM264/M254Poorly tightened 48 V earth wiring in the mild-hybrid system (fire risk)Mercedes-Benz has issued several recalls (2022-2025) because the 12 V and 48 V earth connections of some cars with a 48 V system may be poorly tightened: resistance rises, the connection heats up and a fire cannot be ruled out. The official workshop checks them and repairs them if necessary in an hour or more.
- High severityFrequency: Occasional1.9 TDIUnit injector tappet wear and injector wiring damageOn the unit injector system, the tappets that operate the injectors can wear if the oil is not changed on time, and the injector wiring can be damaged by contact with oil, causing misfires or loss of power.
- Critical severityFrequency: CommonRover 75Seat SRS connector fault with airbag and seatbelt warning light onAuto Express warns that the Rover 75's seat SRS connector can cause the airbags to fail, and dealers were fixing it with revised connectors. The Dutch APK inspection puts the airbag or seatbelt fault warning among the most frequent defects across almost all series.
- Critical severityFrequency: OccasionalAlfa Romeo GiuliettaShort circuit from badly routed wiring that can prevent gear shifting (KBA campaign, 2010-2015)Yes: according to Germany's KBA, on Alfa Romeo Giulietta cars built between 2010 and 2015 inadequate cable routing could cause a short circuit and, as a result, gear-shift failure.
Frequently asked questions
Can I drive with code P2135?
Only as far as you need to reach a garage. The car usually goes into reduced power and the engine may cut out or stall, which is dangerous in traffic.[1][2]
What does it mean that signals A and B do not "correlate"?
That two redundant throttle (or pedal) sensors should give values related to each other and the ECU sees them as inconsistent, so it trusts neither and limits the engine.[1][2]
Does the throttle need replacing?
Often yes, because the sensor is usually part of the throttle body, but wiring, connectors, supply and earth must be ruled out first, as they give the same symptoms.[2][3]
Is any relearn needed after the repair?
Yes, the technical source says to carry out the throttle and pedal relearn the car requires, clear the code and drive so that the monitor checks the correlation again.[2]
Will I pass the MOT with code P2135?
If the code has switched on the engine warning light, no: with that light on, the inspection records a serious defect, and on Euro 5 and Euro 6 cars the ITV (Spain's roadworthiness inspection, similar to the MOT) also reads the OBD diagnostic system. Repair the fault before you go; clearing the code just before the inspection does not help either, because it counts as a serious defect.[4]
Not sure what is wrong with your car? Describe what you notice in the symptom diagnosis or see all fault codes.
Sources
Every fact on this page links to its source. If you find an error, let us know.
- P2135: Throttle/Pedal Position Sensor/Switch A/B Voltage CorrelationCarParts.com · Technical documentation · consulted 29 October 2026
- P2135 - Throttle/Pedal Position Sensor/Switch A/B Voltage CorrelationAutoDTCs · Technical documentation · consulted 29 October 2026
- OBD DTC Fehlercode P2135CarWiki · Technical documentation · consulted 29 October 2026 · in German
- Desmontando mitos: ¿puede pasar mi coche la ITV con el testigo de «avería motor» encendido?Diariomotor · Motoring press · published 8 March 2021 · consulted 2 October 2026 · in Spanish