[hfdtaylor]

My 89' vert is only producing base boost, and there's no voltage at the APC valve connector while the engine is running, so there must be a fault with the APC system somewhere... Thought I'd start by checking the connections on the APC box, but I can't find the damn thing anywhere! My manual says it should be behind the right wing, but it ain't there. I've also checked behind the left wing and under the rear seats, but no joy.

Whilst sorting various other problems, I've discovered the Engine ECU, ABS ECU, cruise control ECU, but I can't recall seeing anything with 'APC' stamped on it...

I'm beginning to wonder if the APC box has been removed at some point... If somebody could please tell me EXACTLY where it should be, at least I can confirm whether it's there or not... Thanks!

 

[Jezzadee]

Left wing, in front of the fuse box. It is a black (or red) plastic box. I would post a pic but I hent gart one. :cheesy:

 

[hfdtaylor]

Thanks Jez, but can't see it. Check out this pic (please excuse the crap photography)... See what you think...

 

[unkleG'sif]

should be where the red box is in this pic..... (altho yours may be black)



its worth remembering that not all cars had them fitted as standard.
check if you have an intercooler, or a valve with 3 pipes going in/out mounted on the radiator/next to the coil

G

 

[hfdtaylor]

Definitley should have one - it's got the intercooler, APC valve, knock sensor etc...

Looking at your pic, my ABS ECU is where your APC box is. Mysterious indeed...

 

[unkleG'sif]

not actually mine (i wish), just nicked off an advert on ebay:nono;

 

[Jezzadee]

Interesting. It's possible that if someone really didn't know what they were doing that they pulled out the APC and fitted an MBC instead. Do you happen to have one of these:

situated more or less where the arrow points, connected to the wastegate in this pic here?:

Note the absence of an APC in the lower left corner because it is an ex-LPT.

 

[hfdtaylor]

Hmm, can't see anything resembling that little gizmo. As you can see, its all rather standard and boring round there.... And with ref to your photo Jez, that hole in the left hand corner is taken up by a large ABS ECU! I've read and re-read the text on this box and it is definitley for the brakes...

 

[unkleG'sif]

hmmmmmm

i thought abs boxes were under the rear seats

 

[Fakie]

So did I.

Does the box on the wing have a code number on it ?

 

[Matthew]

On an '89 car, the ABS ECU is mounted on the left-hand inner wing exactly as shown in the first picture.

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[hfdtaylor]

<Response to DRG23>
Not on mine! All there is under the rear seats is the motor/hydraulic pump for the roof and an associated relay board (and lots of change - mostly foreign coins unfortunately ).

Let it be said here and now that I WILL find that APC box. Tonight I'm going to indulge in my favourite past time - cable tracing!!! I'm getting excited just thinking about it...

 

[unkleG'sif]

On an '89 car, the ABS ECU is mounted on the left-hand inner wing exactly as shown in the first picture.

well every day is a school day - as they say
G

 

[Matthew]

School day for me too - I didn't know where the ABS box was supposed to be, so had to look in the Saab service manual :cheesy:

BTW, the extra fuse box rearward of the ECU is used exclusively by the ABS system (according to the manual :cheesy: )

If the APC box isn't on the LH inner wing, then it probably ain't in the car at all! Look down the LH inner wing and see if there's a large rectangular plastic connector down there.

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[hfdtaylor]

Nope. Had a good look around for any unconnected bits of wiring loom, but couldn't find anything...

I know the APC system is supposedly seperate from the main engine ECU, but any chance Saab could have integrated the two at some point? This is probably a bit unlikely, as there is a seperate fuse for the APC...

 

[Matthew]

Nope :cheesy:

PM me the car's VIN and I'll use the EPC to decode it, see if that turns up anything useful (such as: the car's an LPT afterall with partially-retrofitted APC system).

This is quite a mystery, because the ABS ECU is indeed exactly where the APC box should be.

News just in: According to the EPC, from MY90 onwards Saab put the ABS ECU... under the rear seats! The ABS fuse box also moved to the rear of the inner RH wheel arch.

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[john-w]

Do you have a boost gauge in the instrument cluster??

 

[john-w]

A few pictures iv'e just taken showing the ABS relay under the seat & the APC box on the n/s inner wing, my car is a 1990 Carlsson.

 

[Alex]

Where do the wires go which connect to the top of the APC solenoid?

 

[pda]

perhaps its been retro fitted with a APC unit from a earlier C900 turbo model ie pre-1986 so the APC unit (14 pin model) will be under the rear seat :roll: :roll:

just a thought

HTH Paul

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