P2BAD on Peugeot: causes, affected engines and fix

Documented faults in Peugeot engines that can trigger P2BAD

Grouped by engine or model, from most to least important. These are faults with AdBlue, with the EGR valve and with the particulate filter: not all of them will necessarily set the code, and only a diagnosis confirms the cause on your car.

2.0 HDi

In 508 I, 3008 I, 3008 II, 5008 I, 5008 II, 307 and 3 more models

- High severityFrequency: CommonEmissions controlDPF clogging on additive-type systems (Eolys/cerine)The additive-type diesel particulate filter (DPF) of the 2.0 HDi clogs relatively easily on short journeys, especially on the 107/110 and 136-140 hp versions. The anti-pollution warning light comes on and, if ignored, the car loses power and may end up needing a new DPF.
- Medium severityFrequency: Very frequentEmissions controlAdBlue 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: CommonEmissions controlEGR valve blocked by sootThe 2.0 HDi's EGR valve gets coated in soot and sticks, especially on the 107/120 and 136/138 hp versions; it causes jerking, limp mode and the engine warning light, although it can usually be solved by cleaning it.Repair (garage): €200–€350

2.2 HDi

In 406, 407, 607 and 807

- High severityFrequency: CommonEmissions controlDPF clogging with additive, especially on the 128-138 hp versionThe particulate filter (DPF) with additive on the 2.2 HDi has a documented recurring problem in the 128-138 hp version (98 cases out of 277 reviews on fiches-auto); the more powerful twin-turbo versions show far fewer cases. The emissions fault warning light comes on and, if ignored, the car loses power.

1.6 HDi

In 208 I, 301, 308 II, 508 I, 2008 I, 3008 I and 9 more models

2.0 BlueHDi

In 308 II, 508 I, 508 II, 3008 II, 5008 II and Expert III

1.5 BlueHDi

In 208 I, 208 II, 308 II, 508 II, 2008 I, 2008 II and 4 more models

- Medium severityFrequency: Very frequentEmissions controlAdBlue 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

1.4 HDi

In 206, 207 and 1007

- Medium severityFrequency: OccasionalEmissions controlEGR valve clogged with carbonThe EGR valve, which recirculates part of the exhaust gases to reduce emissions, can seize or clog up with the carbon those gases carry. It appears in a noticeable minority of the reports collected for the 68 hp version.

2.2 MultiJet / BlueHDi (Stellantis)

In Boxer III

- Low severityFrequency: OccasionalEmissions controlAdBlue (SCR) system: the warning light may not come on if the urea doser failsStellantis is correcting with software a fault whereby the warning light may not come on if the AdBlue urea injector stops working (Boxer, Jumper and Movano 2020-2022) or if the SCR diagnostics fail. The declared risk is to emissions, not safety.

Common causes of P2BAD on any make

From most to least likely, according to the sources.

1Faulty NOx sensor or poor electrical connection.^[1][2][4]
2Damaged wiring and connectors, or poor contact, in the NOx sensor and its circuit.^[1][2]
3Dirty or faulty EGR valve.^[1][2]
4Fault in the SCR system or AdBlue dosing.^[1][2]

What to check first

The first diagnostic steps, from the most likely and cheapest to check to the most expensive.

1Read all the codes and save the freeze frame data. An advanced scanner with manufacturer data is preferable to a basic reader; check which other codes are stored.^[2]
2Clear the code, carry out a road test and watch on the scanner when the fault reappears or whether it remains present.^[2]
3Check the wiring and connectors of the NOx sensor and the other sensors in the system: loose connections, corrosion or short circuits.^[1][2]

Full guide to P2BAD: symptoms, diagnosis and whether you can drive

Parts related to code P2BAD on Peugeot cars

The parts that most often cause this code. The code points to the circuit, not always the part: diagnose before you buy.

EGR valve
- Buy part at Autodoc (affiliate link, opens in a new tab)
Particulate filter
- Buy part at Autodoc (affiliate link, opens in a new tab)

Affiliate links: if you buy from these shops, MotorFiable may receive a commission at no cost to you. Check compatibility against the registration plate or VIN before ordering. Affiliate links

Frequently asked questions

Which Peugeot engines have faults that can trigger P2BAD?

2.0 HDi (3 faults), 2.2 HDi (1 fault), 1.6 HDi (3 faults), 2.0 BlueHDi (3 faults), 1.5 BlueHDi (1 fault) and 1.4 HDi (1 fault). Each fault has its own page with the affected years and versions, the symptoms and the repair cost.

What does code P2BAD mean on a Peugeot?

Excess NOx: root cause unknown. The control unit has detected that NOx emissions exceed the limit, but has not been able to attribute it to a specific cause in the system (hence “root cause unknown”). CarWiki summarises it as an excess of nitrogen oxides with no identified origin, which may be due to a problem in the exhaust or the engine and should be checked by a specialist workshop. It is a generic OBD-II code: it means the same on a Peugeot as on any other make.^[1][2][3]

Can I keep driving with P2BAD?

Garage soon. The sources do not set a timeframe. CarWiki recommends a specialist workshop check because emissions exceed the limit, and PartsAvatar mentions that power may be reduced. As the code does not point to a specific part, it is worth diagnosing soon rather than changing parts on a hunch.^[1][2]

Sources

Every fact on this page links to its source. If you find an error, let us know.

OBD DTC Fehlercode P2BAD | NOx Überschreitung – Ursache unbekanntCarWiki.de · Technical documentation · consulted 31 October 2026 · in German
Error Code P2BAD: What It Means & What To Do?PartsAvatar · Technical documentation · published 1 June 2022 · consulted 31 October 2026
p2bad Generic DTC: NOx Exceedence - Root Cause UnknownDTCSearch.com (OBD Solutions) · Technical documentation · consulted 31 October 2026
Qué es un catalizador SCR: funcionamiento, AdBlue y mantenimientoRACE · Motoring press · consulted 31 October 2026 · in Spanish