ECC fault codes interpretation and remedial advice, please

[andreweorr]

Hi All,

First of all, huge thanks to Jod T5 and a few others here and elsewhere for the great guidance on making a led flash code reader. My '96 850R auto does not have a diagnostic port under the bonnet but it does have the OBD II plug under the coin tray. A cheap (£30) diagnostic reader scan tool worked a treat and found no emissions-related codes. I used my newly assembled flash code reader today to get x2 codes relating to the ECC system.

My car does the 20-second A/C and Rec light blink. The damper do not work at all. The centre dial does nothing and the rec function does not seem to do anything. In both cases, no motor is heard to work when activating any setting and there is no redirection of air through any vents. The blower works, the temp dials work, the Auto function seems to work on the blower but obviously has no effect on the damper motors.

The codes I pulled are 2-3-1 and 2-3-3, circuit open or shorted to power for the ventilation and floor/defrost damper motor position sensors respectively. A good read through various forums has made me realise that the damper motor in question might be broken, the moving rods/axles may have cracked and failed, or the printed circuit board inside might be bunged up with grease. In any case, I'll have to get into these motors to find out more.

Can anyone estimate the hours required by a professional Volvo specialist, and therefore labour cost, to carry out the diagnostic work and then how much replacement motors might cost, if available?

To be honest, I don't quite understand what is meant by "open or shorted to power (12V). Can anyone explain what has happened here - has a circuit closed and not able to open (disconnect)? What might this mean in terms of diagnosing the repair required?

Thanks all for your wisdom and patience reading this!!