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Recently I had someone come to me with the same issue. We fixed it by marrying a new used ecu. It's been about 2 weeks. So far so good. Let's hope it stays that way.

Did an sps programming as well.
 
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Because replacing with a used ecu. The program on it might not be for your exact model year. So it's better to program it to match with your VIN. Not just marrying.
 
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P0687 Solved, well at least for me

All,
After fighting this for months and based on the brilliant work by Foxtrapper, I, with significant nudging from my wife, bit the bullet and bought a new ECM. I went the new route as I was told by multiple sources that trying the ebay route was dangerous as it may not work. Total cost was about $1100 for the part and programming.
Painful, but the car has been rock solid for a month now. Since it is my wife's car and we do live in Texas and it is mid summer, this just had to get fixed. Still cheaper than a few car payments and she just loves the car.

Best of luck to all.

David
 
Thanks! Just the answer I was looking for.
I'm in the process of about to bite the same bullet.

Where did you purchase the ECM from or did the shop procure it for you?
 
I used a shop here in the Dallas area that has been repairing Saabs for 40 years. They only do Saabs. I had them purchase the ECM to avoid any issues with getting the correct unit. I have been told the ECM is year and VIN specific. It just wasn't worth it to me try to sort through all of that on ebay.
The company is Frenchs Saab. http://www.frenchssaab.com/
Just over $800 for the ECM and ~300 to install and program. Once I gave them the go ahead the unit arrived overnight and was installed and programmed by the end of day. Worth it in the end.
Hope this helps.
David
 
Discussion starter · #29 ·
Baby steps. Just got my Tech II clone. Still don't have a function TIS so I can't change things on the car, but I can read the car. Only a few piddly codes (door lock error, top sensor error, etc). No ECU errors. But, that might be because of the F2 reset I have installed.

Fun watching the troubles morph. The past two weeks, it's been screwing around with my cruise control. It doesn't always engage, then might start drifting up and down until it disengages. Previously, it was having fun with my climate control and my seat heaters.

But always, a P0687 code.
 
Discussion starter · #30 ·
And we now have success. It's been several days and several hundred miles, no codes, no limp mode, just normal driving.

Junkyard ECU or ECM was the fix.

Bonus, the engine runs much smoother too, especially at idle.
 
Discussion starter · #31 ·
Final follow-up, because what seems to be fixed isn't always.

But in this case, it is. It's been months and nary a check engine light or real running problem. A bad ECU was indeed the problem, replacement with a junkyard one was indeed the fix.
 
Final follow-up, because what seems to be fixed isn't always.

But in this case, it is. It's been months and nary a check engine light or real running problem. A bad ECU was indeed the problem, replacement with a junkyard one was indeed the fix.
Thanks for reporting back! ;ol;
 
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Final follow-up, because what seems to be fixed isn't always.

But in this case, it is. It's been months and nary a check engine light or real running problem. A bad ECU was indeed the problem, replacement with a junkyard one was indeed the fix.
Did you use the tech II clone you mentioned earlier or did you take it to a shop? If you used the clone to marry it, could you please tell which one you used?
 
Wow, foxtrapper, that was simply a mesmerizing read to see how you fixed that problem. So, here were are, summer in Southern California and my 2004 9-3 throws a P0687 and my A/C stops working. Just as the temps hit mid 90's.

Through a friend I have access to a Tech 2 but I need to get a used ECU. There's a 2008 9-3 in my local junk yard. Does anyone know if the ECU on the 08 9-3 will work in an 04 9-3? Both models are sedans.
 
Discussion starter · #37 ·
Does anyone know if the ECU on the 08 9-3 will work in an 04 9-3?
I rather don't think so, but I'm far from certain.

More important, as I recall, is finding one with the right part or serial number on the unit. That way you're replacing like with like. There frequently are a number of them up for sale on ebay.
 
I have a saab same situation ive re wired and bypassed and still even worse now i bought it drove it 18 miles and been in a knock down drag out since so im done im selling it custom body kit rims dont have time for this time taking brain racking chaos anyone looking i have 2004 93 turbo torqoise beautiful but stubborn bit..... Lol she can go for 12 obo
 
Some more updates, without a fix or ECU swap yet.

Last night, while steadily and repeatedly throwing the P0687 code and going into what I call a limp mode it was showing a very steady and consistent pattern with regards to tripping this code.

If I cleared the code and was idling or on light throttle, it would reset the code and check engine light in a second or two.

But, if I hit the throttle and stayed on it when I cleared the code, it would stay cleared as long as I stayed on the throttle. As soon as I lifted my foot, the check engine light would pop up. Even played with dragging the brakes, so I could stay floored for 30 seconds or so. The check engine light would stay off until I backed off the throttle.

The only thing moving mechanically is the throttle blade and motor. There is not and never has been any indicator of a problem with this. The electronic valves on the turbo and bypass? They aren't actuated directly, but they would get a different signal as soon as I backed off the throttle. These valves check out just fine.

So in some ways, it leads me back towards the ECU, but not clearly or perfectly. This scenario wasn't 100% of the time either, more like 90% of the time.

Reading the codes was also showing the P0445 code popping up at the same time as the P0687 code. A short in the evay valve circuit. Except, that valve works just fine and the wiring is excellent and there's no indication of a short. Perhaps another ECU false thing and another vague indicator of the ECU being bad.

Dunno. Just posting this for thoughts from others, as well a record for me.
I have the same problem with my 2006 Saab 9-3 p0686 in p0687 I think it's the ecu. I replace the module for p0606 about a year ago now have p0686 p0687 goes into limp mode clear code and i can drive it about 10 mile and then resets
 
I've been told that you need to shove the accelerator to the floor and insert key, turning over the engine to get it to start without the limp mode or shuddering I get when my car throws its fit. Can anyone tell me if the Ignition control module and the Ionization Control Module are the same, I can't find Ignition control module anywhere but see the Ionization one
 
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