P2188: Mixture too rich at idle (bank 1)
At idle, bank 1 gets too much fuel. Often a leaking injector, a purge valve stuck open or an air flow sensor giving a wrong reading.
| Code | P2188 |
|---|---|
| System | Engine and transmission |
| Group | P21xx, Throttle, injection and emissions |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What P2188 means
At idle, the ECU has to take a lot of fuel away on bank 1 and reaches its limit without correcting the mixture. Extra fuel at idle usually comes from something adding fuel when the engine needs very little.
Most common causes
- Evaporative purge valve (fuel vapour canister) stuck open
- Injector that drips or does not seal
- High fuel pressure from a faulty regulator
- Dirty or faulty mass air flow sensor
- Coolant temperature sensor that always reads cold
- Fuel diluted engine oil feeding vapour through the crankcase ventilation
Symptoms
- Engine warning light on
- Rough idle
- Fuel smell from the exhaust
- Hard starting when hot
- Higher fuel consumption
Can you drive with P2188?
With care You can drive, but a rich mixture burns more fuel and can harm the catalytic converter over time. Do not leave it too long.
Open the bonnetthe in-depth explanation
How to check it
With the engine warm and idling, watch the fuel trims live, then briefly disconnect and plug the purge valve hose and see if they move back towards zero. If they do, the purge valve is the main suspect.
How to read and clear P2188 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 P2188 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
- P2184 The engine 2 coolant temperature sensor gives a lower signal than normal
- P2185 The engine 2 coolant temperature sensor gives a higher signal than normal
- P2186 The engine 2 coolant temperature sensor fails now and then
- P2187 Mixture too lean at idle (bank 1)
- P2189 Mixture too lean at idle (bank 2)
- P218A The throttle actuator B control system idle position needs its learning
- P218C Throttle or fuel inhibit circuit B operates out of range or performs incorrectly
- P218D The throttle or fuel inhibit circuit B signal is low
- P2100 Throttle actuator A control motor circuit open
- P2101 Throttle actuator A control motor circuit range or performance
- P2102 Throttle actuator A control motor circuit low
- P2104 Throttle control system: forced idle
What does code P2188 mean?
At idle, the ECU has to take a lot of fuel away on bank 1 and reaches its limit without correcting the mixture. Extra fuel at idle usually comes from something adding fuel when the engine needs very little.
Can you drive with P2188?
You can drive, but a rich mixture burns more fuel and can harm the catalytic converter over time. Do not leave it too long.
How do you clear P2188?
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, P2188 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.
