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P2BAC: NOx exceedance: EGR deactivated

The ECU has switched off the EGR system because of a fault and nitrogen oxide emissions are over the limit. Usually appears alongside another EGR code.

Code P2BAC at a glance
CodeP2BAC
SystemEngine and transmission
GroupP2Bxx, Engine and emissions
TypeGeneric: it means the same on every make
Can you keep driving?With care

What P2BAC means

EGR recirculates exhaust gas to lower nitrogen oxide (NOx) emissions. When it detects a fault in that system, the ECU may disable it as a precaution. This code warns that, with EGR off, the car is polluting above the permitted level. There is almost always another code explaining why.

Most common causes

  • Another stored EGR fault that caused it to be disabled
  • EGR valve sticking, dirty or with a failed motor
  • Damaged EGR valve connector or wiring
  • EGR position sensor or air flow sensor giving wrong readings
  • Blocked or leaking EGR cooler

Symptoms

  • Engine warning light on
  • Often nothing noticeable when driving
  • Sometimes loss of power or limp mode
  • Will fail an emissions inspection while active

Can you drive with P2BAC?

With care You can drive with care, but get to a garage soon: the car is over-polluting and on some models power is limited until it is fixed.

How to check it

Read all stored codes, not just this one: the one about the EGR (circuit, position or flow) is the one to fix first. This code usually clears once the underlying cause is sorted.

How to read and clear P2BAC with Final OBD

Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P2BAC with this same explanation and whether it’s confirmed, pending or permanent.

With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.

Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.

P2BAC is a generic code, so it means the same on any make, for example on Alfa Romeo, Dacia, Kia, Opel / Vauxhall, Toyota, Škoda. See what Final OBD does on your car in makes and models.

What does code P2BAC mean?

EGR recirculates exhaust gas to lower nitrogen oxide (NOx) emissions. When it detects a fault in that system, the ECU may disable it as a precaution. This code warns that, with EGR off, the car is polluting above the permitted level. There is almost always another code explaining why.

Can you drive with P2BAC?

You can drive with care, but get to a garage soon: the car is over-polluting and on some models power is limited until it is fixed.

How do you clear P2BAC?

With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P2BAC comes back.