1996 850 GLT OXS readiness on/off, inspection, intermittent CEL zionx thread from WDYDTYVT diary

Post by **abscate** » 16 Jul 2019, 11:01

lets try to find the 1996 electrical diagram and post it up and hash it through.

(Ive promised Volvo I won't post these as a mod, but you can do it.)

Post by **ZionXIX** » 16 Jul 2019, 12:11

All data shows this diagram for the fan cooling relay. I appears that 1 line comes directly from the positive battery terminal and 2 lines make their way to the ECU and it looks like there is a a bypass in the relay itself to the ecu. Picture from all data.

Post by **ZionXIX** » 16 Jul 2019, 12:45

Full pdf print out

Post by **abscate** » 16 Jul 2019, 12:59

Monitor yellow wire on ECM, pin 22, to see if 12V is broken when you key off. I don't see how that could happen, but thats how you diagnose, one step at a time

Post by **ZionXIX** » 16 Jul 2019, 17:58

Well the plot thickens. Backprobed the yellow and yellow white wires on the cooling fan relay and got 12v with key off. Pulled the ecu and found pin A22 and measured 12volts with key in all positions and off. So the ECU has power at all times. I have no idea why it has alzheimers.

Post by **bmdubya1198** » 16 Jul 2019, 18:02

Just be careful probing ECU pins like that. They can get damaged very easily!

Post by **ZionXIX** » 16 Jul 2019, 18:11

bmdubya1198 wrote: ↑16 Jul 2019, 18:02 Just be careful probing ECU pins like that. They can get damaged very easily!

I was nice and gentle....I only used the tip of the probe

Post by **abscate** » 16 Jul 2019, 18:21

You got B+ voltage right? Battery voltage to nearest 0.1V ?

Post by **abscate** » 16 Jul 2019, 18:23

Check voltage at Fuse 11/1 and then at pin A12 on the ECU for same voltage reading, to nearest 0,1V

Check pin A26 for battery voltage to nearest 0.1V

Post by **ZionXIX** » 16 Jul 2019, 19:03

Where is fuse 11/1?

1996 850 GLT OXS readiness on/off, inspection, intermittent CEL zionx thread from WDYDTYVT diary

Re: 1996 850 GLT OXS readiness on/off, inspection, intermittent CEL zionx thread from WDYDTYVT diary