04' CTT secondary air control

[A.H.]

Greetings from Finland

 

Car is blowing the 5A control circuit fuse for the secondary air injection pumps and therefore throwing the P2259 code, it also has intermittent "brake booster fault" and I have a feeling these are related to each other. I'm suspecting an relay issue since the pumps are fine(tested) and the fuse is for the control circuit. I also removed and tested the vacuum pump for the brake booster and it's also fine. '

 

Has anyone had any similar issues? Where's the control relay located? I did look for info on the site (a great one!) but so far no good.

 

I'm also looking for an exhaust upgrade, sec-decat and rear section to be precise, but the pricing on those I have found has been plain silly. Any helpfull directions?

Edited July 20, 2015 by A.H.

[A.H.]

Found diagrams for the relays and fuses. Will check later today.

[A.H.]

Checked both relays, OK. Still blows the 5a control circuit fuse. Ideas will be appreciated.

[Loren]

F12 (5A) controls the secondary air pumps as well as the water after-run pump relays.

I would pull the relays individually (secondary air - then after-run pump) and see if you can narrow down the problem area.

[bigbuzuki]

Secondary air pumps have been known to fail.

The impellers disintegrate and prevent the motor from turning.

You could try electrically disconnecting the pumps and replace the fuse to see what happens.

[A.H.]

I have tested the pumps and those are perfectly fine. Jammed pump would drain a whole lot of current and most certainly blow out the large feed fuse for the relay(s).

 

The problem I'm having is on the control circuit for the relays. The current present in the control circuit should be very minimal, therefore the 5A fuse. I would gues that ecm applies ground to the relays when the circuit needs to be energized, only thing that can blow the control circuit fuse is a short to ground between the fuse and the relay or a short to ground IN the relay. Failed coil in the relay would very possibly cause this. Sec-air-pump relays are very simple, and i have to say very robust in construction (70A..) and I doubted i would find the culprit there - as I did not.

 

Actually I could measure the drawn current to the relays separately, I did test them from a battery unfused. I will dig into this more this evening, hopefully i'll get it sorted soon as the bugger seems to disable closed loop lambda operation in any case of a malfunction - without enabling mil- light. - no good.

 

When i'll get this storted i can get to changing out the valveblock in the autobox..

[A.H.]

Finally got around looking further in this;

 

Cold start; remove pump relays and afterrun coolant pump relay, fuse in place - Start the car - Fuse blows immediately (no relays attached). BUT if I immediately plug in all the relays, and replace the Fuse, both air pumps start, fuse does NOT blow and all is well in the kingdom of waterbox.

 

And it gets even more interesting; Last time I fiddled with these It seems to have cured itself, even though I did nothing??

 

My best bet is that the insulation on the control wiring is cracked or stripped in the waterbox, and moisture&dirt has been causing a short to ground condition in the circuit. We'll see if it will come back someday.

 

Anyway for the time being there are no issues, sec air pumps work every morning, no codes or blown fuses. Car runs flawless and on E85. (I have a Finnish Flexfuel conversion kit on it.)

 

 

[bigbuzuki]

Definitely sounds like your defect is with the wiring under the water box.

How difficult is it to lift the water box and check the wiring?

[A.H.]

Not that hard. If the fault ever comes back i'll dig in the waterbox.

[dpatel710]

I am having this same set of issues - brake booster light, secondary air pump code/CEL, and the coolant after run pump is not running. 04 CTT.

 

I wrongly assumed that the coolant after run pump motor died and replaced the pump. After reading this thread, I found the F12 5A fuse to be blown. I replaced the fuse, started the car, and the brake booster pump works again but the coolant after run pump still does not function in "rest mode". I could not test if the SAI pumps work as the car was already warm. Visually, the relays look fine - no corrosion or obvious defect. I have a voltmeter, is there a way to test these? 

 

Can you guys please offer further guidance on how to troubleshoot this? My car heater is very weak at idle without the pump running and it is getting cold in the NE! 

Edited November 3, 2018 by dpatel710

[dpatel710]

Found another post that documents this with pictures - 

 

https://rennlist.com/forums/cayenne-955-957-2003-2010/929076-fuse-12-in-the-waterbox-2.html