P05F4: The exhaust after-treatment power relay control gives a lower signal than normal
The exhaust after-treatment power relay control gives a lower signal than normal. It is usually the part, its wiring or a connector with poor contact.
| Code | P05F4 |
|---|---|
| System | Engine and transmission |
| Group | P05xx, Speed, idle and auxiliary inputs |
| Type | Generic: it means the same on every make |
How to read and clear P05F4 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 P05F4 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
- P05F0 The AdBlue pump power supply voltage is above normal
- P05F1 The AdBlue pump power supply voltage circuit has got stuck
- P05F2 The AdBlue pump power supply voltage circuit has got stuck
- P05F3 The exhaust after-treatment power relay control has a broken or disconnected
- P05F5 The exhaust after-treatment power relay control gives a higher signal than
- P05F6 The exhaust after-treatment power relay control circuit has got stuck
- P05F7 The exhaust after-treatment power relay control circuit has got stuck
- P05F8 The AdBlue heater control unit gives readings outside the normal range
- P0500 Vehicle speed sensor malfunction
- P0501 Vehicle speed sensor range/performance
- P0502 Vehicle speed sensor circuit low input
- P0503 Vehicle speed sensor intermittent, erratic or high
What does code P05F4 mean?
The exhaust after-treatment power relay control gives a lower signal than normal. It is usually the part, its wiring or a connector with poor contact.
How do you clear P05F4?
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, P05F4 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.
