P0492: Secondary air injection system insufficient flow (bank 2)
The system that blows air into the exhaust from cold is not delivering the expected air on bank 2. Usually the air pump, the valve or a hose.
| Code | P0492 |
|---|---|
| System | Engine and transmission |
| Group | P04xx, Emissions control |
| Type | Generic: it means the same on every make |
| Can you keep driving? | Yes, no rush |
What P0492 means
Some petrol engines have a pump that blows fresh air into the exhaust during a cold start, so the catalytic converter warms up faster and emissions drop. The ECU uses the oxygen sensors to check that this air arrives. Here it finds not enough is reaching bank 2. Bank 2 is the side opposite cylinder 1, so this code only applies to V or flat engines.
Most common causes
- Secondary air check valve or combination valve clogged with carbon or moisture
- Air hose loose or split, or a broken vacuum control hose
- Faulty secondary air pump or water inside it
- Fuse or relay for the pump at fault
- Faulty electric or vacuum control valve
Symptoms
- Engine warning light on
- Loud noise, or no noise at all, from the pump in the first seconds after a cold start
- The car usually drives normally once warm
Can you drive with P0492?
Yes, no rush It only works for the first few minutes from cold, so it does not affect driving or the engine. It needs fixing for the inspection, but without hurry.
Open the bonnetthe in-depth explanation
How to check it
Start from cold and listen near the engine: the secondary air pump usually hums for a minute or two and then stops. If you hear nothing, check the fuse and relay; if it runs but the code sets, look at the valve and hoses.
How to read and clear P0492 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 P0492 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
- P048E The exhaust pressure control valve position sensor gives a higher signal than
- P048F The exhaust pressure control valve position sensor fails now and then
- P0490 High signal in the EGR valve control
- P0491 Secondary air injection system insufficient flow (bank 1)
- P0493 The coolant fan runs too fast because its clutch is locked
- P0494 The radiator fan is turning slower than it should
- P0495 The fan speed is above normal
- P0496 EVAP system high purge flow
- P0400 Exhaust gas recirculation (EGR) flow malfunction
- P0401 Exhaust gas recirculation (EGR) flow insufficient
- P0402 Exhaust gas recirculation (EGR) flow excessive
- P0403 EGR control circuit malfunction
What does code P0492 mean?
Some petrol engines have a pump that blows fresh air into the exhaust during a cold start, so the catalytic converter warms up faster and emissions drop. The ECU uses the oxygen sensors to check that this air arrives. Here it finds not enough is reaching bank 2. Bank 2 is the side opposite cylinder 1, so this code only applies to V or flat engines.
Can you drive with P0492?
It only works for the first few minutes from cold, so it does not affect driving or the engine. It needs fixing for the inspection, but without hurry.
How do you clear P0492?
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, P0492 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.
