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YOUR RESEARCHP0491/2 + Misfires Problem - 986 Forum - The Community for Porsche Boxster & Cayman Owners
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Check chances
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Suggestion · Original poster
Is there anything specific i can check my chances?
P0491/2 + Misfires Problem - 986 Forum - The Community for Porsche Boxster & Cayman Owners
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Leading evidence: 'Check chances' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check chances' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suggestion · Original poster
I opened the engine cover and cannot see any hoses broken, so i may have to start checking deeper.
P0491/2 + Misfires Problem - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Check first
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Suggestion · Original poster
Thanks, do you have any idea which one i can start checking first ?
P0491/2 + Misfires Problem - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Run car
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Suggestion · Original poster
Im a bit worried to run the car with that many misfires, but maybe running it for 15 seconds will be fine
P0491/2 + Misfires Problem - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Suggestion
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.
P0491/2 + Misfires Problem - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Run diagnostics
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
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Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Suggestion
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.
P0491/2 + Misfires Problem - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Suggestion
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.
P0491/2 + Misfires Problem - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Run diagnostics
No successful repair reported for this finding.
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Reported fixes
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Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
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.
P0491/2 + Misfires Problem - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Test pump;
No successful repair reported for this finding.
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Read evidence and context
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
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.
P0491/2 + Misfires Problem - 986 Forum - The Community for Porsche Boxster & Cayman Owners
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8 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
986Forum: 1 discussions
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Generation: 20261026T122219Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
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
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?
