DTC P0410 but no CEL

steve3007 · Post by **steve3007** » 14 Dec 2005, 17:08

Ran a friends OBD2 software on my 98 V70 T5 and it returned a P0410 code for the Secondary Air Injection System.

However, CEL is not showing. I turned on/off the car a few times, still no CEL (it works since it is lit when I first turn on the car).

Does the CEL turn off if the problem no longer remains but the code is not cleared? How long (if ever) before the ECU clears an old code?

Post by **dosbricks** » 15 Dec 2005, 20:48

steve3007 wrote: Does the CEL turn off if the problem no longer remains but the code is not cleared? How long (if ever) before the ECU clears an old code?

The CEL will turn off after several complete drive cycles for most codes if the problem is fixed or doesn't recur. It does remain in the ECU's memory, probably until it's cleared.

Some faults have to occur more than once to set the CEL.