Opel/Vauxhall 1.6 CDTI «Whisper Diesel» (GM Medium Diesel, B16DTx)AdBlue (SCR) system and NOx sensor
AdBlue (SCR) system failure on Euro 6 versions on the 1.6 CDTI
Why this rating?
Medium severity: It can leave you stranded or get worse if ignored, without destroying the engine.
Frequency occasional: We have documented only one direct report from a Mokka X 1.6 CDTI with this problem; the rest of the evidence (AdBlue crystallisation, repair cost) comes from the specialist press on Euro 6 diesels in general, not specific to this engine. We treat it as occasional in the absence of more published cases linked to Opel.[1][2][3]
Symptoms
- AdBlue system warning on the dashboard, sometimes with a countdown of remaining starts until it is resolved.[3]AdBlue warning: other faults that cause it · Garage soon
- Reduced power when the SCR system detects a dosing fault, according to the specialist press consulted for Euro 6 diesels in general.[3]Less power: other faults that cause it · Monitor
Why it happens
The BlueInjection system injects AdBlue (a solution of urea and water) into the exhaust to meet the Euro 6 standard, in force for this engine since September 2015.[4]
AdBlue can form deposits and crystallise inside the dosing injector or the pump, especially if it is topped up with a non-approved additive, which obstructs correct dosing of urea.[2]
A Mokka X 1.6 CDTI owner with 150,000 km describes the AdBlue system as the main reason for his bad experience with the car, calling it an "arnaque" (a rip-off).[1]
If it is not repaired: An AdBlue system fault can leave the car in low-power mode and should be repaired as soon as possible, with bills that, according to the specialist press, easily exceed €1,000 if the SCR catalyst has to be replaced.[3]
Affected cars and years
The BlueInjection system with AdBlue is fitted to the Euro 6 versions of this engine, in production since September 2015; we have not been able to pin down which exact engine codes correspond to Euro 5 versus Euro 6 in each car, so we do not restrict this fault to specific versions.[4]
| Version | Years | Codes |
|---|---|---|
| 1.6 CDTI 95 hp (B16DTE/B16DTU, 2014-2018) | 2014–2018 | B16DTEB16DTU |
| 1.6 CDTI 108-110 hp (B16DTL/B16DTN/B16DTU/D16DTI, 2014-2019) | 2014–2019 | B16DTLB16DTNB16DTUD16DTI |
| 1.6 CDTI 120-122 hp (B16DTJ/B16DTC, 2014-2018) | 2014–2018 | B16DTJB16DTC |
| 1.6 CDTI Turbo ecoFLEX 134-136 hp (B16DTH, 2013-2020) | 2013–2020 | B16DTH |
| 1.6 BiTurbo CDTI ecoFLEX 150-160 hp (B16DTR/D16DTR, 2015-2019) | 2015–2019 | B16DTRD16DTR |
Models fitted with the affected versions
Opel
- Opel Astra J2014–2015
- Opel Astra K2015–2019
- Opel Zafira Tourer C2013–2019
- Opel Insignia A2015–2017
- Opel Insignia B2017–2022
- Opel Meriva B2013–2017
- Opel Mokka A2014–2019
How much it costs to repair
Includes: Diagnosis of the SCR system and replacement of the dosing injector, the pump or, in the worst case, the complete SCR catalyst.[2][3]
General industry figures for AdBlue/SCR system failures on Euro 6 diesels, not specific to this engine: we have not found a published quote in Spain for the 1.6 CDTI in particular.
Prices in Spain, including VAT. A workshop hour costs on average €38–66 at independent garages and €77–134 at dealerships in Spain, depending on the region and the brand. How we calculate costs
How to check for it before buying a used car
- Check the maintenance history of the AdBlue system and ask whether an additive other than the approved one has ever been used.[2]
- Check that the AdBlue warning light is not on and that there are no messages counting down remaining starts.
Parts needed
The part or kit that fixes this fault, according to the sources.
AdBlue (SCR) dosing injector module[2]
Replaced when it becomes blocked by AdBlue crystallisation or by the use of a non-approved additive, preventing urea from being dosed correctly into the exhaust.
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How to prevent it
- Always use AdBlue certified to the ISO 22241 standard and do not wait for the warning light to come on before checking the level.[2]
Recalls, campaigns and claims
As of 27 September 2026, we have no record of recalls, campaigns or extended manufacturer warranties for this fault. Check with an official dealer using the chassis (VIN) number: they will tell you whether the car has any outstanding campaign.
What owners say
Frequently asked questions
Does the Opel 1.6 CDTI AdBlue system cause problems?
A Mokka X owner with 150,000 km points to it as his main complaint about the car; the fault (crystallisation, incorrect dosing) is a known problem in the SCR systems of Euro 6 diesels in general, not exclusive to Opel.[1][2]
How much does it cost to repair the AdBlue system?
According to the specialist press, this type of fault usually exceeds €1,000 and can approach €2,000 if the complete SCR catalyst has to be replaced, although these are not figures specific to this engine.[2][3]
How can I avoid an AdBlue fault?
Always use an ISO 22241-certified additive, avoid letting the tank run completely empty and do not ignore the warning light if it comes on.[2]
What can you do now?
We will put you in touch with a partner only if you authorise it in the form.
Other 1.6 CDTI faults
- High severityFrequency: OccasionalTimingNoise and early wear of the timing chain and its tensionerThere are verifiable reports of chain noise and timing tensioner replacement on the 1.6 CDTI, in one case at only 9,200 km. There is no manufacturer campaign or official failure statistics, so it is a real risk but not precisely quantified.
- Medium severityFrequency: CommonEmissions controlSuspected software shut-off of the EGR valve (emissions investigation)Between 2016 and 2018, Germany's KBA and the Frankfurt prosecutor's office investigated whether Opel switched off the EGR valve on its Zafira and Insignia diesels above certain conditions, increasing real-world NOx. Opel denied it and, according to the sources consulted, there is no record of a penalty or of a corrective campaign having been carried out.
More faults with AdBlue on other engines and cars
- 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.
- Medium severityFrequency: Very frequent2.0 BlueHDiAdBlue (SCR) tank and pump failureOn the 2.0 BlueHDi, the AdBlue tank can crystallise or fail and show a warning with a countdown to the point where the engine will not start. It is the most frequently cited fault of this engine: Stellantis compensates owners of diesels built up to August 2020, with no definitive fix.Repair: €1,000–€1,500
- Medium severityFrequency: CommonBMW N43/N46Injector, ignition coil and NOx sensor failures (N43)On the direct-injection BMW N43, failures of the injectors, ignition coils (mainly in 2007-2008 units, now rare after a BMW service action) and the NOx sensor of its lean-burn combustion have been documented. The indirect-injection N46 does not have that sensor and does not suffer these failures.
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Sources
Every fact on this page links to its source. If you find an error, let us know.
- Fiabilité Opel Mokka X - avis et pannes des propriétairesFiches-auto.fr · Owners' forum · consulted 27 September 2026 · in French
- El aditivo de AdBlue que debes usar para evitar una reparación de 2.000 euros en tu coche diéselAutopista.es · Motoring press · published 1 April 2026 · consulted 27 September 2026 · in Spanish
- Twin dosing en diésel: el fallo que dispara una avería de más de 1.000 euros en el tallerMotor16 · Motoring press · published 22 September 2026 · consulted 27 September 2026 · in Spanish
- GM Medium Diesel engineWikipedia (inglés) · Other source · consulted 27 September 2026