P2259 code meaning
AIR System Control B Circuit Low
Powertrain system Generic code P22xx codes Check engine light
What P2259 means
P2259 is the low-level fault of the second secondary air control circuit, B. A second circuit exists where an engine uses two AIR pumps, two relays or a separately switched air valve; circuit A keeps its own codes P2257/P2258. A low reading usually means the control wire has contact with ground. If the relay is switched to ground by the ECM, such a short can energise it permanently, so the pump or valve keeps running after the warm-up phase and may overheat. No manufacturer publishes a threshold for circuit B; GM merely names P2259 in the keyword list of its connector-check bulletin PIP5094 for 2014 and older models. For circuit A, GM's 2018 tables judge the low-side driver over 20 of 25 samples as a Type B fault. CARB requires that secondary air systems be monitored. The engine itself runs normally.
P2259 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2259
- MIL on
- Secondary air pump audible for longer than usual or while warm
- Blown fuse of the secondary air pump after a long run
Common causes of P2259
- Most likelyControl wire of circuit B chafed against the body or engine and shorted to ground
- PossibleRelay or air valve B with a shorted winding
- Less likelyCorroded connector at relay B or the air valve
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 P2259 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). |
| 59 | The exact fault in that area. |
What to do next
- Note P2259 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 P2259
What does P2259 mean?
P2259 means "AIR System Control B Circuit Low". P2259 is the low-level fault of the second secondary air control circuit, B. It is a generic code, so it means the same on every make.
Is it safe to drive with P2259?
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 P2259 fail an emissions test?
Yes, it can. P2259 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 P2259 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2259 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.