Hi Guys,

I'm having a weird SAP problem.

My SAP cycles on and off for about one minute after starting for periods of about 3 seconds. Sometimes, it cycles on and off even after the car is warmed up.

What could be causing this? I know the tests and stuff that have been posted up here, but those were for SAP's that either didnt work at all or stayed on permanently...

 

Well the fact that the SAP pump is turning off and on isn't a problem unless there is a fault code, however the pump shouldn't be audible. So if you are hearing that vacuum cleaner noise it means the bearings in the pump are getting worn out and its on its way out. Most SAP pumps will turn on and off 4 times during cold start in the winter.

 

Hi Auditech,

Thanks for the reply.

My concern is that it only runs in short bursts (3 seconds). I thought it was supposed to stay on for longer periods. I can hear the relay constantly clicking under the steering wheel.

I also do get the intermittent warm up catalyst code...

 

Now that would be on the strange side, it should activate for periods of about 30 seconds. You need to get yourself a multimeter and check the power source at the pump and see if the power supply is being supplied at the correct rate or not. If its turning off at 3 seconds or so you need to track down that relay that might be causing the problem.

 

What does the SAP do?

 

The SAP is a emissions pump that pumps air into the exhaust to speed up the heating of the catalyst in the Cat converters.

AudiTech...I tried swapping the relays with another that I knew worked (it is the same relay as the ABS pump).

The power going to it is fine...for the 3 seconds.

All vacuum lines etc are fine...I dont think its the solenoid...

Seeing as to how its kicking on, the fuse is likely ok...

Any other leads on this one?

 

Is the ECM registering a fault code? It could still be the solinoid. Did you try manually activating the pump with the vag com yet to see if it works? (block 77 or 78)

 

No fault code other than an intermittent emissions code.

VAGCOM test on the Pump is fine. It works perfect.

Maybe an ECM issue?

 

Whats the emissions code?