Emissions control: EGR, DPF, catalytic converter and AdBlueManufacturer codeUrgency: Monitor
Code P1435: secondary air pump relay shorted to ground (VW/Audi)
What code P1435 means
On Volkswagen and Audi, the control unit detects a short to ground in the secondary air pump relay circuit; the pump blows air into the exhaust to reduce emissions after a cold start.[1][2]
Other makes use it for something else: Peugeot, Citroën and Ford, an air-conditioning coolant temperature circuit out of range; Honda, a battery charge/discharge imbalance. Confirm the make.[1]
Original definition (SAE J2012): Secondary air injection (AIR) pump relay - short to ground[1][2]
Causes of P1435
From most to least likely, according to the sources.
Symptoms
- Engine warning light on.[1]Engine warning light: faults that cause it
How to diagnose P1435
In order: from the most likely and cheapest to check to the most expensive.
Can I keep driving with P1435?
Monitor
The sources say nothing about severity. It affects an emissions system, not engine lubrication or cooling; it is worth fixing to pass the MOT.[1][2]
Documented faults related to P1435
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
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
What does P1435 mean on a Volkswagen or Audi?
And on a Peugeot or Citroën?
According to the sources, a range problem in the air-conditioning coolant temperature circuit.[1]
What should be checked first?
The wiring and the secondary air pump relay.[2]
Will I pass the MOT with code P1435?
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.[3]
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.
- P1435 - TroubleCodes.net (definiciones por fabricante)TroubleCodes.net · Technical documentation · consulted 29 October 2026
- P1435 - Manufacturer Controlled DTCDTCSearch · Technical documentation · consulted 29 October 2026
- 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