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P0687 Fun

40K views 40 replies 16 participants last post by  aerojon  
#1 ·
Gads this is fun to chase down and fix.

I can go for days with no error, and other times it can trip it over and over again dozens of times within a minute (have an android phone, Torque app and a blue tooth ELM327 adapter).

About half the time it cuts the A/C compressor off, about 1/4 the time it kills turbo boost (or perhaps it's retarding timing and dropping boost as a result). No pattern to this that I can find, yet.

Have noticed that there seems to be a heat aspect to it tripping this code. As in hotter weather generally makes it happen more. Sitting in heavy traffic also makes it happen more and repeat much more quickly. As in clear the code, trip the code. That fast, and over and over again. Once traffic clears and air flows, it tends to stop or slow down.

I have noticed it is most prevalent to tripping the code in the first 10-20 minutes of driving. After it's gone through this, it tends to trip the code far less. Though the A/C compressor has a habit of staying off, even after the code is cleared.

There also seems to be a relationship to violence, for lack of a better word. As in hard braking or hard throttle can sometimes produce the code at the same instant the event takes place.

Swapped the relay, no change. Opened and inspected relay, including cleaning contacts. Everything was and is fine, or at least appears to be.

Cleaned the grounds and all wiring connectors, as well inspected the wires. Everything was fine, and is now even more so. Tripped the code in 3 miles after I put it all back together.

I wish the WIS was clearer and more informative on this code and the wiring. Not just where the wires go, but the logic of what is triggering things and why.

Almost everything describes the P0687 code for a Saab as being a high voltage out of the relay. Which seems mighty weird as there is no source of high voltage available. Some other things I've read list the code as short to ground, which also seems highly unlikely.

But, I have read a few others that talk about failure to receive voltage, and holding voltage too long. That seems more plausable with a relay. Either heat soaking and failing to actuate or close, or sticking and failing to open. Hmm.

I may just buy a relay to try as a new relay. I don't expect anything from it and I hate to waste money.

Something I haven't done yet and don't really want to do is to open up the ECU to inspect it for solder fractures.

I don't have a Tech II reader (yet), but I wonder if that might reveal more details and help me chase this one down. It's not something I've seen mentioned in other threads regarding this and other similar OBD code problems.
 
#28 ·
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
 
#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.
 
#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.
 
#36 ·
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.
 
#38 ·
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
 
#40 ·
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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