intermittent p600, p700, p863 - service transmission - again

[EngineeringBloke]

It's time for the annual inspection this month and the check engine light came on for the fuel tank leak detection pump. Had my mechanic replace the pump. He found some suspension issues and 2 tires at end of life (which I knew).

I love Michelin pilot sport A/S and checked online to find that the 3+ are being superseded with a new Pilot 4. Of course, my 3+ and the one remaining 3 are 215/55R16 but the new tires are only available in 205 or 225 widths. The online store, and the local installer that I chose to use, both advised against running the old size and new size - the width difference is not significant (under 5%) but there is a small difference in diameter. I decided to be excited about 4 new tires and got four 4's. Plus there is a rebate this month.

So over the weekend, just when I thought I was ready for the inspection, the car had a lurch 50 feet from returning to its parking spot - a reoccurrence of my p600, p700, p863 codes and a service transmission message. The indicator next to the shift lever stayed in 'D' after I turned the key to pos 1, but after turning all the way off and then on again, the transmission was restored to normal.

Of course, I still had to clear the stored codes and am waiting for the emissions to become ready (Torque app showing O2 and Catalyst not ready). I'll be doing a longer drive this afternoon to try to clear these for tomorrow morning MA state inspection.

Although the transmission problem has gone away, it occurs multiple time a year and at inconvenient times. I would like to fix it so it stops occurring but am not sure what's wrong.

p0600 - "powertrain serial communications link"
p0700 - "p0700 powertrain transmission control system (MIL request)"
p0863 - "powertrain"

This appears to be an electrical/comms issue.

I had pulled both ECU and the transmission computer, and used contact cleaner on the computer and mounting electrical contacts previously. Although it was not a particularly hot day, I do wonder about overheating under the dash or at the AT computer. It seems to occur after driving hard when I have slowed for a turn or heavy traffic. Perhaps reduced cooling airflow in engine compartment.

Any ideas? I don't have VIDA/DICE, just my Torque app and a ODB2 Bluetooth adaptor.

[RickHaleParker]

P0700 & P0863 translate to the same Volvo code TCM-530B.

Effectively you only have two Volvo DTCs TCM-530B & TCM-E000.

This applies to both TCM-530B & TCM-E000.
Cause:

• Contact resistance or oxidation in the terminals.
  Open-circuit in the control area network (CAN) wiring.
  Short-circuit between the control area network (CAN) wiring.
  Internal fault in the transmission control module (TCM).
  Internal fault in another control module in the same part of the control area network (CAN).

Control modules on the High speed CAN bus.
TCM, ECM, BCM, SAS, SUM, DEM.