P2436: Secondary Air Injection System Air Flow Pressure Sensor Circuit Range/Performance Bank 2
What to do
The car drives normally. This often means air genuinely is not reaching the exhaust on this side rather than that the sensor is wrong — ask for the check valve and pipework on this bank to be inspected for blockage. Testing needs a properly cold engine, so the car may need to stand overnight.
What this code means
The bank 2 secondary air flow sensor is reporting a figure the module cannot reconcile with what it commanded. The reasoning is at P2431: this is the code most likely to be reporting a real blockage rather than a sensor fault, because the failures of this system are physical and this sensor is the only one positioned to see them.
On a two-bank system the narrowing at P2435 applies — one bank showing no flow points at that side's check valve and pipework, while both point at the pump or switching valve they share.
Likely causes
Start here
- Failed secondary air check valve · moderate
- Blocked secondary air pipework · moderate
Less common
- Faulty secondary air flow sensor · moderate
- Seized secondary air injection pump · moderate
- Faulty secondary air switching valve · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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