Emissions control: EGR, DPF, catalytic converter and AdBlueGeneric OBD-II codeUrgency: Garage soon
Code P20E8: adBlue pressure too low
P20E8 means: reductant (AdBlue) pressure too low.[1][2] The AdBlue circuit (the reductant of the SCR system) has a pressure sensor monitored by the ECU. P20E8 is logged when the measured pressure falls below the calibrated minimum: the pump cannot build or maintain the pressure needed for dosing.[1][3]
What code P20E8 means
The AdBlue circuit (the reductant of the SCR system) has a pressure sensor monitored by the ECU. P20E8 is logged when the measured pressure falls below the calibrated minimum: the pump cannot build or maintain the pressure needed for dosing.[1][3]
While the pressure is not right, the AdBlue is not injected as it should be and the SCR system cannot reduce NOx properly. In Jaguar Land Rover's 2016 bulletin for several Land Rover and Range Rover models, the instrument cluster may show an AdBlue dosing fault message with a countdown in kilometres after which the engine will not restart. The code refers to the circuit pressure, not the tank level.[1][3][4]
It is a generic OBD-II code (it starts with P2), with the same definition on any make.[5]
Original definition (SAE J2012): Reductant Pressure Too Low[1][2]
Causes of P20E8
From most to least likely, according to the sources.
- 1Leaks, damage or loose electrical connectors at the tank, the supply line or the AdBlue dosing module.[3][4]
- 2Blocked AdBlue filter or supply line, or problems in the pressure line.[2][3]
- 3Weak or failed AdBlue pump.[2][3][6]
- 4Blocked dosing injector or valve, or one with urea crystals, especially on cars used for short journeys that do not reach operating temperature.[2][3][6]
- 5Faulty reductant pressure sensor, reporting the pressure incorrectly.[1][2]
- 6Frozen AdBlue or a failed tank heater in cold weather.[3][6]
- 7Reductant purge valve that is not working.[2]
Symptoms
- Engine warning light on.[2][4]Engine warning light: faults that cause it
- An AdBlue dosing fault message may appear, along with a countdown in kilometres after which the engine will not restart.[4]AdBlue warning: faults that cause it
- If it is not repaired, dosing stops and a power-limiting sequence begins.[3]Limp mode: faults that cause it
How to diagnose P20E8
In order: from the most likely and cheapest to check to the most expensive.
- 1Read all the codes and resolve any others that are stored first: Jaguar Land Rover warns that they must be investigated before continuing with the procedure.[4]
- 2Carry out a visual inspection of the AdBlue tank, the supply line and the dosing module: leaks, damage and loose electrical connectors. Check the wiring too.[2][4]
- 3Check the filter, the pump, the lines and the dosing valve or injector, which are the components that build and maintain the pressure, and look for urea crystals in the injector and lines.[3][6]
- 4With the manufacturer's diagnostic tool, run the AdBlue system priming and pressure test routine and reset the SCR quality monitor. For certain 2016 Land Rover and Range Rover models, Jaguar Land Rover then describes a drive cycle of at least 15 minutes at urban speeds and with a light load, after which the warning clears on its own once the system completes its check.[4]
- 5If the code returns, measure the reductant pressure and check the pressure sensor, wiring and connectors with a multimeter.[2]
- 6In cold weather, check whether the AdBlue is frozen or whether the tank heater is working.[3][6]
- 7Replace a component only when the tests point to it. Electrical faults in the pump or the heater, built into the tank module, usually mean replacing the whole tank assembly.[6]
Can I keep driving with P20E8?
Garage soon
Do not wait for the countdown to finish. The Jaguar Land Rover bulletin describes a warning that announces how many kilometres remain before the engine will not restart, RACE states that a fault in the system can prevent the engine from restarting, and Fleet Rabbit that dosing stops and a power reduction sequence begins. The exact time limit depends on each engine's calibration.[3][4][6]
Documented faults related to P20E8
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
AdBlue (SCR) system and NOx sensor: the most serious faults by engine and car
- Medium severityFrequency: Very frequent1.5 BlueHDiAdBlue tank and pump failure1.5 BlueHDi engines built up to August 2020 can suffer failures of the AdBlue tank pump module, with a "no engine start" countdown. The whole tank is usually replaced and Stellantis contributes to the cost up to 8 years.Repair: €1,000–€1,500
- Medium severityFrequency: Very frequent1.6 HDiAdBlue tank and pump fault (1.6 BlueHDi)The 1.6 BlueHDi engines (2013-2019) suffer from the AdBlue tank defect of Stellantis diesels: an emissions warning appears with a countdown until starting is prevented. Replacing the tank, with the integrated pump, costs over €1,000 (price in Spain), but there is an extended warranty of up to 8 years.Repair: €1,000–€1,200
- Medium severityFrequency: Very frequent2.0 HDiAdBlue tank crystallisation and failures (BlueHDi)On the 2.0 BlueHDi with SCR and AdBlue (from 2013), the system's tank, pump or sensors can fail or crystallise: a warning light appears, sometimes a false one, and if ignored the car may end up not starting. The OCU has reported it in Spain and Stellantis compensates some of those affected.Repair (garage): €800–€1,200
- 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.
P20E8 by make
Documented faults that can trigger P20E8 in each make's engines and cars.
Frequently asked questions
Why does P20E8 appear if the AdBlue tank is full?
Because the code refers to the circuit pressure, not the tank level. The pump cannot build or maintain the dosing pressure, and the most commonly cited causes are leaks, a blocked filter or line, a weak pump, a blocked or crystallised injector, a faulty pressure sensor or, in the cold, frozen AdBlue.[1][2][3]
Can I keep driving with P20E8?
Only to get to the garage, and without delay: the warning may come with a countdown in kilometres after which the engine will not restart, and the ECU ends up limiting power. Do not wait for it to reach zero.[3][4][6]
What is the difference between P20E8 and P20EE?
P20E8 concerns AdBlue circuit pressure: dosing fails before it reaches the catalytic converter. P20EE concerns efficiency: the SCR catalyst converts less NOx than expected, and it can also be caused by a poor AdBlue supply or quality. If both appear at the same time, the sources recommend fixing the AdBlue pressure and quality first.[3]
Is it fixed by replacing the AdBlue pump?
Not necessarily. First rule out leaks, loose connectors, a blocked filter and lines, a crystallised injector and the pressure sensor. Jaguar Land Rover, in its bulletin for some 2016 Land Rover and Range Rover models, indicated a visual check of the system and then running a priming and pressure test routine followed by a drive cycle.[2][3][4]
Does P20E8 mean the same on all makes?
Yes. Codes that start with P2 are generic OBD-II codes and have the same definition across all manufacturers. What changes is the most likely cause, which depends on each system.[5]
Will I pass the MOT with code P20E8?
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.[7]
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.
- P20E8 - Urea (AdBlue) Fluid Pressure Too Low | TaTThe Automotive Technician (TaT) · Technical documentation · consulted 2 October 2026
- PartsAvatar.ca - Solution of OBD Code Error P20E8PartsAvatar · Technical documentation · published 2 June 2022 · consulted 2 October 2026
- SCR & DEF Codes Explained: P20EE, P207F, P20E8 Complete Fleet GuideFleetRabbit · Other source · published 23 September 2026 · consulted 2 October 2026
- SSM72610 - DTC P20E8 - Reductant pressure too low - signal above allowable range (boletín TOPix de Jaguar Land Rover)Jaguar Land Rover · Manufacturer · published 29 January 2016 · consulted 2 October 2026
- On-board diagnosticsWikipedia · Other source · consulted 2 October 2026
- Qué es un catalizador SCR: funcionamiento, AdBlue y mantenimientoRACE · Motoring press · published 23 September 2026 · consulted 2 October 2026 · in Spanish
- 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