P04AC: The evaporative emission system purge control valve B gives a lower signal than
The evaporative emission system purge control valve B gives a lower signal than normal. It is usually the part, its wiring or a connector with poor contact.
| Code | P04AC |
|---|---|
| System | Engine and transmission |
| Group | P04xx, Emissions control |
| Type | Generic: it means the same on every make |
How to read and clear P04AC 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 P04AC with its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
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 an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- P04A8 The exhaust pressure control valve position sensor B gives a lower signal than
- P04A9 The exhaust pressure control valve position sensor B gives a higher signal than
- P04AA The exhaust pressure control valve position sensor B fails now and then
- P04AB The evaporative emission system purge control valve B has a broken or
- P04AD The evaporative emission system purge control valve B gives a higher signal
- P04AE Fuel vapour filter purge valve B works poorly or is stuck open
- P04AF The evaporative emission system purge control valve B has got stuck
- P04B0 The valve controlling vapours during refuelling has an open circuit
- P0400 Exhaust gas recirculation (EGR) flow malfunction
- P0401 Exhaust gas recirculation (EGR) flow insufficient
- P0402 Exhaust gas recirculation (EGR) flow excessive
- P0403 EGR control circuit malfunction
What does code P04AC mean?
The evaporative emission system purge control valve B gives a lower signal than normal. It is usually the part, its wiring or a connector with poor contact.
How do you clear P04AC?
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, P04AC comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
