Secondary Air Injection Problem.

[passatrip]

Ok, so I've been coming up with a code involving Secondary Air Injection system. The code is Secondary Air Injection System: Incorect flow detected. I went and felt, and it seems as if there is no flow. I was wondering: a, what exactly the secondary air injection system does, b, if it has a fuse and/or relay and where it would be, and c, if anyone else has had this problem and how ther resloved it. Thanks. BTW, this is for a 2000 Passat 1.8t. Thanks.

[tryin2vw]

The SAI system is intended to help warm the Cat faster by injecting excess air into the exhaust and fuel into the engine during the initial 90-120 seconds the car is started when warm. You will hear the SAI pump run typically on a cold start-up or occasionally when the cat is below proper operating temperature.

On a cold start-up, do you hear a "whine" that seems to quit after about a minute and a half? That is the SAIP running.

General failures are caused by:

Clogged hoses (clean if clogged or buy new)
Vacuum lines that are leaking (replace if braided OEM with high temp silicone)
Fuse or relay being bad (Fuse is 40A and both are in the box with the ECU under the windshield on the drives side of the car)
Combination Valves that are leaking
Bad SAI Pump

The first two above fixed my SAI system issues.

[spitpilot]

The SAIS consists of;
Pump, large air tubing from pump to "kombi" valve, kombi valve a vaccum operated valve that opens into the exahust manifold to allow air from the pump to flow (V6's have two one behind each cylinder head), little vaccum lines that carry control vaccum to the Kombi vlave from the vaccum control valve (on the V6 this is up on the top of the motor along with the vac contols for the intake manifold tuning system, don't know where it is on 1.8T motors...trace little cloth covered vac hose back from Kombi valve. Starting with the eziest and cheapest fixes...the little control vaccum hoses crack (you look at em from the outside they look fine, but the're cracked under the woven cloth and leak out the control vaccum so Kombi valve (s) don't open. The air tubing from the air pump to the Kombi valve is obstructed or cracked open..you should see this. The control valve isn't sending vacccum to the kombi valve (test this by removing the control tube from the solenoid valve, have someone start car and put finger over valve vaccum port to see if you feel vaccum). Kombi vlave diaphram is broken/valve is stuck..you can test this by connecting a vaccum pump (one of those vaccum test/brake bleed hand pumps) to the control vaccum port, disconnecting the air tube so you can blow into it. Pull a vaccum on the Kombi you might even hear it open, and/or blow into the air hose...if you can't blow air into the exhaust manifold then the Kombi valve is shot. The air injection pump is shot..these usuall make "death throw" noises as they fail so if you hear bad whine louder than ususal begin on cold start up and then die out (only to come back on for a brief period after driving the car a bit...thats the system test function it tuns on for 30 seconds or something like that to test system) then suspect pump failure. If you need a pump or for that matter the Kombi or vaccum control vales try 1stvwparts..I bought a pump for my V6 from them for $225 that the local dealer (errr stealer) wanted $460 for!

[passatrip]

Thanks sooooo much.

[Golfguru17]

since its been cold here mines been running like you said when i first start it but its a really loud whinning sound. Is that from a lose fan bearing and should i replace it?

[tryin2vw]

Sounds like the suction or discharge is clogged. Typically what happens is the warm exhaust gasses condense in the suction tubing and collect due to condensation. This can be due to a stuck combi valve, bad check valve or bad actuator solenoid.

I suggest that you remove any piping that you can (the plastic parts and metal if you can) and clean with PCV cleaner. Then check the other items to make sure all are ok.

[passatrip]

Why are VWs the only cars that have secondary air injection. You know, it's wierd, today the pump came back on and started working again. I'm still getting the code though .

[tryin2vw]

Sounds like a bad electricla connection somewhere. The relay is about $40 at the dealer or 1stvwparts. Check the electrical connections if you can.

If it just started working again, then it will take several starts before the code clears and the CEL turns off.

[passatrip]

I can turn the CEL off with Vag-Com, but I can't find the relay on 1stvwparts.

[tryin2vw]

141 951 253B I believe is the current number.

[passatrip]

Doesn't seem to be on there

[spitpilot]

Relay's are ez to test..slap 12V on em and see if they close contacts...you're sure the vacc lines to control the Kombi valves are all OK..a crack there can be hard to find...my little "one way check valve" cracked right where the hose nipple went into the body..I couldn't see it on visual inspection..so I just decided to change all those #@%#$^ little vac hoses and when I touched the one way valve it just broke at first contact....replaced the valve, all the little hoses and the hard lines and elbow kit that VW sells to retro fit the Kombi valve vacc system on the V6..evidently they've had trouble with that set up..the little hoses and rubber connectors are subject to alot of heat back under the engine there and I'm bettin vW has seen lots of probs with the original thinner connectors so they now have thick rubber elbows to connect the hard vac lines to the Kombi valves..cost me about $15 for the kit at 1stVWparts.com...Zeb there chased the kit down for me after I asked for "parts to connect the Kombi valve vaccum on V6"...worked like a champ!

[passatrip]

I'll test the relay, and if it turns out it is bad, I'll get one from the dealer. Thanks alot.

[roger.argueta]

Hey, this is the best answer and knowledge base about the secondary air system (i've check about 15 or 20 Threads from very long time ago) This is my problem (a little off-set from the creation of this Thread) with my Passat: B5 2.8 V6 30-valve, AHA:

Everything on my SAIS it's OK, except that the PUMP does not activate while the SAIS is working (cold start). The Pump is OK, I test it alone and it work with direct current, so I conclude that the PUMP is not the problem, as it is the current or power supply of the PUMP: I tested both wires that may activate the PUMP with a multimeter and both black and red wire measures GROUND, neither one gives +12V.

I've already checked the relay j299 (in the black box next to the brake fluid) and it's OK: it pass or bridge GROUND current from the Black Wire to the Black/Red Striped Wire (even when I don't know where this Black/Red wire goes to). I ignore if there is a FUSE or other things to check between the PUMP and the relay or other components. I read somewhere there is a FUSE near the relay j299 but I didn't found anything inside the black box.

About the other components of the SAIS, I tested them: the Kombi valve (Both) opens due to the vacuum generation, the PCV or PVC is new. This is the only Code I receive from the VAG-COM (i don't know the number right now) but it's related to the Secondary Air Intake or System, and obviously might be related to the Secondary Air PUMP that is not activated every time SAIS is working.

WHAT SHOULD I BE MISSING?

A good text I found is this one (in a 13 pages manual i have in pdf):

Secondary air system
Function
The secondary air system blows air in behind the
exhaust valve for 65 seconds during the cold
start (+15 C - +35 C coolant temperature). This
produces an oxygen rich exhaust gas, causes
afterburning and reduces the heating-up phase
of the catalyst. Activation occurs from the
Motronic control module (J220) via the
Secondary Air Injection (AIR) pump relay -J299-
to Secondary Air Injection (AIR) valve -N112-
and combi-valve. Additionally after each
subsequent engine start (up to max. 85 C
engine temperature) the secondary air system
will after a 20 second delay switch in for 5
seconds during idling and will be checked by the
On Board Diagnostic (OBD).

sorry about my spelling, I'm from Central America, Guatemala, French.
Thanks

[tryin2vw]

Looking at the relay in the ECU box, a jumper can be used across pins 30/87 (the big spades) to test the SAI pump. On cold start-up, 12 should be measured across pins 85/86.

[roger.argueta]

Tnks! I'll try both. I'll be posting the results tomorrow, I think