1985-1998 [Subscribe to Daily Digest] |
 | [Main 9000 Bulletin Board | BBFAQ |
Prev by Date | Next by Date | Post Followup ]
Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Depends on how much electronics experience you have Posted by Bill Homer [Email]  (#3427) [Profile/Gallery]
(more from Bill Homer) on Fri, 5 Mar 2004 15:54:26
In Reply to: '93 Aero, BPC solenoid short took out driver in ECU..., bazil burns, Fri, 5 Mar 2004 07:13:13 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I have never taken apart the ECU in a 9000, but have an idea how it works based on normal electronic design practice. This advice may be worth what you are paying for it, though!
My wild guess without looking is that the four large transistors with heatsinks correspond to the drivers for the DI system, one per spark plug - they don't have to be adjacent on the circuit board. From what I have seen elsewhere, there should be several smaller driver transistors for other control functions, including one for each side of the BCP Solenoid. These are probably identical to each other and provide a switched path to ground (or possibly +12V ?), where one of the three transistor legs will end up. Note that if the ECU is a multi-layer circuit board that the run may not be obvious.
One of the other legs will be connected to the pin on the ECU that connects to the solenoid control wire (it may go through a resistor first) - the defective (shorted) side transistor is what you want to replace (or just replace both, transistors are cheap), note the proper orientation of the legs. This is probably made difficult by a weatherproof coating sprayed on to reduce oxidation. I don't know the transistor number offhand, but believe that if you do a search here you might find it - or it could be stamped on the body of the transistor. Be sure to use proper grounding technique to avoid electrostatic discharge damage when you play with the ECU.
Let us know if you actually do this repair, I may be in the same boat resolving my base boost issue. I would like to have a standby ECU before I attempt it though - anyone want to loan me one for a '94 (no TCS)?
posted by 136.182.2...
, Fri, 5 Mar 2004 15:54:26 <-- Viewing This Message
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
