Secondary Air Pump

[MaximusB]

My car recently got a fault code for secondary air pump low flow bank 2 (verified with ISTA).

Just a couple of weeks prior I got a few faults related to pre-cat o2 bank 1 and 2. The faults would jump around between each bank without me changing anything other than clearly the codes. I had dealt with o2 sensor faults several times before and it was always bad exhaust gaskets just before the o2 sensors. But it never triggered secondary air pump codes.

Could exhaust leak just before the cat or bad o2 sensor also trigger SAP low flow fault?

I checked the gaskets last night and they were definitely bad, crumpling and breaking into pieces. Some of the wire mesh in the gasket were also exposed on both sides. Will be putting in new gaskets and new o2 sensors tonight and see.

Anyone had SAP low flow fault that wasn’t actually caused by the SAP system? I just want to start eliminating all the easy stuff before tearing into the SAP and check valves.

[omgzirra_exe]

Exhaust gasket can cause this, fault o2 can cause this, blown fuse 89 can cause this.

worse case you're going to squeeze your hand into the firewall area and try to remove teh SAP clean them or replace them.

[Scrippy]

Confirm the pump does turn on during cold start. By pulling the input air hose from the intake elbow and you should feel suction upon cold start for 20-30 seconds or so. That will prove the pump is running. It should feel like a pretty good suction like a small shop vac. If that works the blow side of the pump goes to a Y-hose to push air into the two exhaust banks at the back of the motor. This will require cold start with the plenum off to reach that Y-hose. If you do get good blow from both sides the next test would be the check valves that allow air into injection runners but not allow air to flow back to pump. If those check out you may have a clogged injection port in bank 2. This will require cleaning with a gun bore brush. I have a thread with pics in the forum. Good luck. INPA will show the flow via MAF & mini.

[MaximusB]

Originally Posted by omgzirra_exe

Exhaust gasket can cause this, fault o2 can cause this, blown fuse 89 can cause this.

worse case you're going to squeeze your hand into the firewall area and try to remove teh SAP clean them or replace them.

It was definitely either the gasket and/or the pre-cat o2. I replaced them last night and reset the o2 adaptation, and everything is good now. Idle is much much smoother than before.

Originally Posted by Scrippy

Confirm the pump does turn on during cold start. By pulling the input air hose from the intake elbow and you should feel suction upon cold start for 20-30 seconds or so. That will prove the pump is running. It should feel like a pretty good suction like a small shop vac. If that works the blow side of the pump goes to a Y-hose to push air into the two exhaust banks at the back of the motor. This will require cold start with the plenum off to reach that Y-hose. If you do get good blow from both sides the next test would be the check valves that allow air into injection runners but not allow air to flow back to pump. If those check out you may have a clogged injection port in bank 2. This will require cleaning with a gun bore brush. I have a thread with pics in the forum. Good luck. INPA will show the flow via MAF & mini.

Yes, I read through your thread and was really hoping I don't need to go through all that. Which was why I wanted to tackle all the easy stuff before diving into taking out the valves and cleaning out the ports. But thank you for documenting your process.

Also in ISTA+ you can activate the secondary pump, don't need to wait for the car to be completely cold and go through the cold start cycle. When ISTA+ activates the pump you can hear and feel the idle changes. When I first ran the test with a bad gasket and/or o2, ISTA was telling me low flow in bank 2, and idle definitely got rough during the test. After I put in new gaskets and o2, ran the test again and ISTA said no fault found in the SAP system. I didn't think I would have a faulty pump since ISTA was saying low flow in bank 2 only. I would assume if the pump was faulty I would get low flow code for both banks or some other code as no air would be going through the MAF when the car would be expecting it.