97 855 GLT EEC Trouble code help Topic is solved

Post by **Chuck W** » 07 Jun 2017, 06:14

Hey all.

Messing with the wife's 97 855 GLT.

We've had issues with the EEC since we picked up the car. PS side will do what it wants, temp-wise, floor dampers don't work, etc.

I made one of the DIY code readers over the weekend and got the following list of codes.

1-2-6
2-1-1
2-2-1
2-3-1
2-3-3
3-2-4
3-2-5
4-1-4
4-1-7

Reading the manual, I came across this...

DTC 2-1-1, 2-2-1, 2-3-1, 2-3-3 & 2-3-5 DRIVER’S OR
PASSENGER’S SIDE DAMPER MOTOR POSITION SENSOR CIRCUIT
OPEN OR SHORTED TO POWER
1) Check if DTCs 1-2-2, 1-2-4, 1-2-6, 2-1-1, 2-2-1, 2-3-1, 2-
3-3 and2-3-5 are present. If all DTCs are not present, there is an
open or short circuit in a wire between ECC control unit and damper
motor which applies to DTC. See AUTOMATIC A/C-HEATER SYSTEM DIAGNOSTIC
TROUBLE CODES table, then go to next step. If all DTCs are present, an
open circuit is present in common ground at ECC terminals A9 and A10.
See Fig 10.

I have no 1-2-2 or 1-2-4 codes but all the rest are there. Looking at the wiring diagrams, it may still lead me to look towards the open circuit in the common ground for the dampers. Perhaps at the connector, or at the common junction for all of those items (Wherever that may be)

Any other thoughts?

The 4-1-4 and 4-1-7 are for the cabin temp sensor intake fans being seized, which are probably just clogged with junk.

Post by **jreed** » 08 Jun 2017, 05:08

The ECC will remember all errors that have occurred, even ones which are rare or no longer active.

I would inspect the intake fans and clean them out if needed. Then reset the codes on the ECC. Run the system for a while to see which codes return. You may indeed have several position sensor circuits that have failed... I have had to clean out three of them on my '97 855 GLT because they get covered by grease dripping down from the plastic gear train.

Post by **Chuck W** » 08 Jun 2017, 10:22

I'll check the fans first this weekend and try and reset the codes.

I've messed a bit with a couple of the damper motors, before being able to read codes, and I get nothing out of them. Pulled them apart, cleaned them, swapped them. Nada. Looking at the wiring diagram, all of the offending motors share a common ground splice, it appears.

Post by **dyn blin** » 08 Jun 2017, 13:35

jreed wrote: ↑08 Jun 2017, 05:08 The ECC will remember all errors that have occurred, even ones which are rare or no longer active....

jreed- thanks for the post, I did not know the codes were persistent.

Dumb question- how do you reset the ECC on the post '96 850's and V70's?

Post by **abscate** » 08 Jun 2017, 15:07

Software, high end scanner, or Volvo Dealer - it won't reset with a battery disconnect

Post by **dyn blin** » 08 Jun 2017, 19:20

abscate wrote: ↑08 Jun 2017, 15:07 ... it won't reset with a battery disconnect

So I've found. No luck with the VOL-FCR either.

Post by **jreed** » 09 Jun 2017, 05:14

I have been able to reset the codes on the ECC. I wrote up the sequence here:
viewtopic.php?f=1&t=50443&start=13

Post by **Chuck W** » 09 Jun 2017, 05:56

jreed wrote: ↑09 Jun 2017, 05:14 I have been able to reset the codes on the ECC. I wrote up the sequence here:
viewtopic.php?f=1&t=50443&start=13

That's my plan when I have time with the car this weekend. Thanks for that post. It's what I was using last weekend.

Post by **dyn blin** » 09 Jun 2017, 11:02

jreed wrote: ↑09 Jun 2017, 05:14 I have been able to reset the codes on the ECC. I wrote up the sequence here:
viewtopic.php?f=1&t=50443&start=13

Missed that one. Great post- thank you!

AKJeeper · Post by **AKJeeper** » 09 Jun 2017, 12:11

abscate wrote: ↑08 Jun 2017, 15:07 Software, high end scanner, or Volvo Dealer - it won't reset with a battery disconnect

I've got a video on how to read and clear the codes with a home made tool.

I'm going to make another one on how to get the system to relearn the damper motor positions at some point in the near future...