P2257 code meaning
AIR System Control A Circuit Low
Powertrain system Generic code P22xx codes Check engine light
What P2257 means
P2257 concerns the control circuit of the secondary air (AIR) pump or its relay, which blows fresh air into the exhaust during cold starts so the catalyst lights off sooner. The code sets when that circuit reads low. GM's 2018 tables (LWE section) watch the low-side driver of the AIR pump control: a resistance of 0.5 ohm or less to controller ground, detected as low voltage with the driver switched off, in 20 of 25 samples of 250 ms with at least 11 V on the powertrain relay, Type B; some controllers also log P0418. VW's 2014 specification books for the CC and Touareg flag a relay control voltage between 0 and 3.26 V. P2258 is the short to power, P0418 the open circuit. Affected cars mainly emit more during warm-up.
P2257 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2257
- Check engine light
- Secondary air pump silent during cold start
- Secondary air flow codes such as P0411 may follow
Common causes of P2257
- Most likelyRelay control wire shorted to ground
- PossibleSecondary air relay with a shorted coil
- Less likelyWater ingress in the relay or pump connector
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Secondary air pumpSai relaySai wiring
What each part of P2257 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 2 | Area: fuel and air metering (injector circuit). |
| 57 | The exact fault in that area. |
What to do next
- Note P2257 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2257
What does P2257 mean?
P2257 means "AIR System Control A Circuit Low". P2257 concerns the control circuit of the secondary air (AIR) pump or its relay, which blows fresh air into the exhaust during cold starts so the catalyst lights off sooner. It is a generic code, so it means the same on every make.
Is it safe to drive with P2257?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2257 fail an emissions test?
Yes, it can. P2257 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2257 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2257 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.