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Old 06-19-2007, 08:07 AM   #1
CJ_Boxster
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Secondary Air Injection Testing without a PST2

Heres some useful info I found on another forum regarding P-codes for the Secondary Air Injection system, I believe its for 2000 and newer boxsters but the poster believes it could also be the same for 99 and older.

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Here is some possible useful info from the PCA site on a forum question regarding secondary air injection faults:
QUESTION:
I appreciate your previous assistance and finally found a operation in Bozeman that could read code for me. Here is the data derived:
1. PO410 Secodary Air Injection Problem
2. P1411 Undocumented Code

They also cleared the code which may or may not last. Where to I start? Thanks
ANSWER:
Both of the faults that you have listed are for the Secondary air injection. P0410 is for cylinders 1-3 and P1411 is for cylinders 4-6. To cause a fault in both banks would have to be from a common user. The most common problem with all the Secondary air injection systems is the cut off valve or the check valve up to 1999. The cut off valve is vacuum actuated by a solenoid. When actuated it allows the air to flow to the exhaust ports in the cylinder heads. To keep the exhaust gasses from going back into the air pump and damaging it the check valve blocks it off. This valve is what they call a one way valve. Both of these valves are actually the same as what was used in the 993's. Having said that we can find a direct correlation between both of these cars having the same problems. Generally the 993 will require the check valve while the Boxster will use the cut off valve. From 2000 on the Boxster uses an improved version that combines both of these valves into one unit.

In the Boxster the air pump is located on the passengers side under the engine cover. The hose that comes off of the air pump goes to the cut off valve unit up to 1999 or the combo cut off valve from 2000 on. On the 1999 and before years there is another hose from the cut off valve that goes to the check valve.

Step 1) To test the cut off valve it will have to be removed and checked. Since the fail rate in the Boxster is so high for this part I would suggest you have a new one to reinstall. Once removed you can hook up a vacuum source to the valve and blow into the valve. Blow in the direction of the arrow and you should be able to do this with no resistance. This should block off all the way when the vacuum source is removed. This test can also be done on the car with a Porsche tester and checked. Should this check out OK then go to the next step below and fallow. This will not usually be necessary.

Step 2) Check the air pump next. This is generally done with a Porsche tester, however you can supply voltage and ground to its wiring to make it run. Pin 1 on the air pump is positive and pin 2 is the negative or ground.

Step 3) Check the vacuum to and from the solenoid valve when actuated. This valve is electrically operated and switches the vacuum on and off to the cut off valve. These have gone bad, but are not as common.

This would conclude the testing for a 2000 or newer Boxster. Should all of the above be correct on a 1999 and previous Boxster, replace the check valve.

This is not Porsche's testing order. I have found this testing order to be more direct for the most common failed parts and for ease of testing. I have listed the part numbers below for the valves.

1999 and pre Cut off valve 993 113 245 00
1999 and pre Check valve 993 113 250 03
2000 and newer Cut off Valve 996 113 249 01
Change-over valve (Vacuum Solenoid) 996 605 123 01



Scott Slauson - PCA WebSite - 6/25/2004
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