Replaced the Lambda sensors which now means the emissions light comes on only when the car is cold, not when I reset it after it is warm.

Scanner comes up with a P2257 Secondary Air Injection System Circuit Low fault which after a bit of searching appears to be the EGR Valve or SAI pump. (Same thing I believe).

Has anyone changed this or had a similiar problem.

 

Hi Nick

not same, 2 different systems. Secondary air is only used after cold start to inject fresh air into exhaust port to mix with combustion gas in hope to get the cat lit off and converting gas quicker. Air injection is done and over with about a minute after start. Egr is exhaust gas fed back into inlet manifold in hope to reduce nox emissions due to inert air taking place of combustable air.

the problem you report is isolated to secondary air pump, the code suggests the pump is being electronically commanded (so not fuse) and perhaps the pump needs replacing because is not supplying volume of gas the system is expecting.

pump unit is located underneath inlet manifold

with the extent of your mods though, just get it switched off in calibration? Easier and cheaper than new pump and labour imo

 

There's a relay for the secondary air pumps which is right next to the Jumper Post + terminal at the front passenger area under the hood...make sure the relay has power and ground..if feeds are live, bench test the relay and you might find its faulty, in which case replace the relay...hehe it's not cheap either

 

Thanks Mike and Irish for the great analysis and tips.

Strange thing is that this is an intermittant fault. This morning cold weather and no light??

It could be the ECU learning the the new lambda probes perhaps? Or the SAI is working intermittently.

Will see how I get along over the next few days.

 

[QUOTE=Vergis;4211373]

Strange thing is that this is an intermittant fault. This morning cold weather and no light??


[QUOTE]

in my experience the intermittent behaviour means the pump sometimes struggles into life to deliver the flow required, the fault code you get backs that up because the code is saying low flow when electronically pulsed. If it was never pulsed or intermittent power would throw up a different code.
the good news is that despite what's going on its a code that can be ignored and just reset. If that bothers you then either turn off in cal or replace hardware

 

[QUOTE=Mike bamford rose;4211378][QUOTE=Vergis;4211373]

Strange thing is that this is an intermittant fault. This morning cold weather and no light??


Interesting. I will probably look to replace it and will do it myself if it doesnt involve taking the air inlet off.

 

check this

 

Can the SAI pump be disabled by simply removing the relay or a fuse, mine is starting to groan sometimes which I presume could be worn bushes/bearings allowing contact of impeller to housing within the pump?

 

I think it was Bing CROSBY that famously said "He was an average guy who could carry a tune", which applies here, the only way to code both SAI and EGR out is with a very simple ECU re-tune - takes seconds!

even if the system was electronically fooled into being connected externally, the make up of predicted Mass Air Flow the ECU is expecting will ping a MIL because airflow is not what it should be, so no other way round the issue

 

Yah you could, it would then be disabled electrically, along with storing fault codes P0412/P2257/P2258..which will cause the Check Engine light to come on because an emissions system is no longer functioning correctly.

Like Bamford said, you have to tune to disable the function which will avoid the check engine light from coming on.

If your sure it's the injection pump that's faulty, replace it...an estimated list part price for the pump is $280+/-USD (call your parts dept for a good quote)..