P0491/2 + Misfires Problem
 

Hey folks, long time no see.

So ive done my research so far for my sudden Misfires: P0306, P0304, P0305,P0302 plus the SAI Codes: P0491,P0492

Ofcourse there is flashing CEL so i stopped driving the car..

I opened the engine cover and cannot see any hoses broken, so i may have to start checking deeper.

Is there anything specific i can check my chances? Since i cant drive the car and im on an island currently so the car would have to be towed back and forth in a ferry to get it fixed..

THANKS AS ALWAYS :cheers:

P0491 Secondary Air Injection System, Bank 1 - Insufficient Flow
P0492 Secondary Air Injection System, Bank 2 - Insufficient Flow

Possible cause of fault
- Electrical fault in power supply or line between relay and secondary air injection pump
- Secondary air injection pump relay mechanically faulty
- Mechanical fault in electrical secondary air valve
- Pneumatic secondary air valve faulty/sluggish
- Electrical fault in secondary air injection pump
- Mechanical fault in secondary air injection pump or secondary air injection pump blocked
- Vacuum system leaking
- Air hose to secondary air injection pump slipped off or constricted

Thanks, do you have any idea which one i can start checking first ? Maybe it would be better/easier/faster (but more expensive) to get a new SAI Pump and check if that is the case?
Or even get the old pump out and get it tested to a local indy around the island ?

Rather than aimlessly replacing parts, you need to start running diagnostics for electrical faults, components failing to activate when power is applied, look for vacuum leaks, etc. That SAI pump cost a couple hundred dollars aftermarket and over a grand at the dealer, and may not be your issue....

Got it, thanks. Maybe i could rule out the SAI pump if i start the car (once dead cold) and listen if the Pump starts whining. If not, i could assume that its a faulty SAI Pump ?

Im a bit worried to run the car with that many misfires, but maybe running it for 15 seconds will be fine

You do not need to run the car to test the pump; using electrical diagnostic tools like a Power Probe, you can unplug the pump and run it from the tool. Some Porsche specific scan tools can also activate it without the car running. And just be aware: It is standard procedure for parts outlets, and particularly dealers, to not accept any returns for ANY electrical or electronic parts; you buy it, you own it, so make sure you really need it first...

Okay so the pump doesn’t start at all. I have located the relay, not sure if it’s broken or not. I’ll search the island if I can find it here in an auto parts but I doubt it(?) so I may end up ordering it online.

I looked the relay box and there is no relay similar to that so I can’t really test it with another relay.

But in any case, shouldn’t the car run fine even when SAI pump is out? Maybe the SAI has locked a valve closed so that the air doesn’t get through?

Nope, the DME would need to be reprogrammed to remove the SAI. You are vainly searching for a cheap,,easy, and quick out, and there isn't one...