Emissions control: EGR, DPF, catalytic converter and AdBlueManufacturer codeUrgency: Monitor
Code P1453: by make (VW/Audi, BMW, Mercedes)
P1453 means: manufacturer-specific: depends on the make. On VW/Audi, an open circuit or short to positive in the exhaust gas recirculation (EGR) temperature sensor; on BMW and Mercedes-Benz, an electrical fault in the secondary air system or the secondary air pump relay.[1][2] On Audi and Volkswagen, the control unit detects an open circuit or a short to positive in the exhaust gas recirculation (EGR) temperature sensor.[1][2]
What code P1453 means
On Audi and Volkswagen, the control unit detects an open circuit or a short to positive in the exhaust gas recirculation (EGR) temperature sensor.[1][2]
On BMW it is an electrical fault in the bank 1 secondary air system, and on Mercedes-Benz, a faulty secondary air pump relay.[1][2]
On Peugeot and Citroën, the source defines it as a fault in the fuel tank pressure relief valve, and on Land Rover, as high current in the EVAP system pressure pump.[1][2]
Original definition (SAE J2012): Manufacturer-specific: Audi/VW EGR temperature sensor open circuit/short to positive; BMW/Mercedes-Benz secondary air injection electrical fault / pump relay defective[1][2]
Causes of P1453
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 P1453
In order: from the most likely and cheapest to check to the most expensive.
Can I keep driving with P1453?
Monitor
The sources give no severity rating. It is a fault in a sensor or an emissions system; it is worth checking to avoid further warnings and an MOT failure.[1][2]
Documented faults related to P1453
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
EGR valve: the most serious faults by engine and car
- Critical severityFrequency: Very frequentBMW B47EGR cooler leaks with risk of engine fireYes: the EGR valve cooler can suffer internal coolant leaks which, mixed with soot and oil, can reach combustion temperatures; BMW has launched several technical campaigns since 2018 to inspect and replace it because of the risk of engine fire.Repair (garage): €500–€1,500
- Critical severityFrequency: Very frequentBMW N57EGR cooler leaks with risk of engine fireYes: like the N47 and B47, the N57 is covered by BMW's service campaign for EGR cooler leaks, which can mix coolant with soot and oil to combustion temperatures. BMW checks free of charge the 6-cylinder engines built between July 2012 and June 2015 because of the fire risk.
- High severityFrequency: Very frequentOM651EGR and particulate filter clogging, and emissions software updatesThe particulate filter and EGR clog up with short journeys, as on any diesel with these systems. In addition, Germany's KBA required software updates on several models with this engine between 2018 and 2021 because of a function that reduced EGR outside a temperature range.Repair (garage): €800–€2,500
- Medium severityFrequency: Very frequentOM642Emissions defeat device (AdBlue/EGR) and software update campaignGermany's KBA found indications of emissions manipulation in cars with the OM642 engine (alongside the OM651): AdBlue dosing and the EGR changed between the test bench and the road. Mercedes-Benz denied it, but in 2018 it recalled hundreds of thousands of diesels in Europe.
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 P1453 mean on a Volkswagen or Audi?
An open circuit or short to positive in the EGR temperature sensor.[1][2]
And on a BMW or Mercedes?
An electrical fault in the secondary air system or in its pump relay.[1][2]
Is it a generic code?
No, it is manufacturer-specific: its meaning changes depending on the make.[1]
Will I pass the MOT with code P1453?
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.
- P1453 - TroubleCodes.net (definiciones por fabricante)TroubleCodes.net · Technical documentation · consulted 29 October 2026
- P1453 - 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