P0506: Idle speed lower than expected
The engine idles at fewer revs than the ECU is asking for. Usually a dirty throttle body or idle valve, or a clogged air filter.
| Code | P0506 |
|---|---|
| System | Engine and transmission |
| Group | P05xx, Speed, idle and auxiliary inputs |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What P0506 means
The ECU sets a target idle speed and opens the air passage more or less to reach it. If the engine stays below target even with the passage wide open, it logs this code. Most often too little air is getting in.
Most common causes
- Throttle body or idle valve coated in carbon
- Very dirty air filter
- Idle valve or throttle motor sticking
- Extra load on the engine (alternator, air conditioning compressor) higher than normal
- Misfire or injection fault robbing the idle of power
Symptoms
- Low idle with vibration
- Engine stalling when stopping or with the air conditioning on
- Engine warning light on
Can you drive with P0506?
With care You can drive, but the engine may stall when you stop, which is awkward and sometimes dangerous. Get it cleaned or checked soon.
How to check it
Compare actual and desired idle speed live, if your scanner shows both, and see how far the throttle is opening. Cleaning the throttle body followed by a relearn fixes many cases.
How to read and clear P0506 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 P0506 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.
Similar codes
- P0502 Vehicle speed sensor circuit low input
- P0503 Vehicle speed sensor intermittent, erratic or high
- P0504 Brake switch A/B correlation
- P0505 Idle control system malfunction
- P0507 Idle speed higher than expected
- P0513 Incorrect immobiliser key
- P0520 Oil pressure sensor/switch circuit malfunction
- P0521 Oil pressure sensor/switch range/performance
- P0500 Vehicle speed sensor malfunction
- P0501 Vehicle speed sensor range/performance
- P0522 Oil pressure sensor/switch low voltage
- P0523 Oil pressure sensor/switch high voltage
P0506 is a generic code, so it means the same on any make, for example on Audi, Dacia, Fiat, Kia, Opel / Vauxhall, Toyota. See what Final OBD does on your car in makes and models.
What does code P0506 mean?
The ECU sets a target idle speed and opens the air passage more or less to reach it. If the engine stays below target even with the passage wide open, it logs this code. Most often too little air is getting in.
Can you drive with P0506?
You can drive, but the engine may stall when you stop, which is awkward and sometimes dangerous. Get it cleaned or checked soon.
How do you clear P0506?
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, P0506 comes back.
Read it on your car
Final OBD reads the faults of every control unit for free, including each make’s own codes, and with Pro explains each one in plain English. Free clears engine faults at no cost.
Coming soon
Mid to late October 2026
If you want to try it in your car before anyone else, send us your email and we will add you as a tester.
info@finalobd.com