2000 Volvo v70 awd xc wagon
Check engine light on.

Following are the codes:

ECM-4801
ECM-530D
ECM-6110
TCM-001F
TCM-E003

Where to begin? What to look for? Etc.
Car won't pass inspection once again.

And you left the dealer without an explanation of what the codes mean?

The ECM are for cat converter efficiency, tranny problem, and engine fan inoperable. TCM are tranny codes.

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My back feels better when I sit in a Volvo seat

The Dealership gave me a print out of the error codes, but it is not in simple English terms to under stand.
When I asked for more info they gave me the standard explanations and that was all.

ECM-4801

CAT Converter was Replaced last January 2014 with a brand new one. At the same time were the O2 Sensors. Both Sensors on the Transmission were replaced last fall. Complete PCV System overhaul was done last summer. Oil changes done every 7K miles with a small oil leak from the cap seal.

ECM-6110 Could that be the Fan Relay which sits above the fan itself? If so, I have a few extra of those units.

The TCM's; as I mentioned above the two sensors on the transmission were replaced last fall and had no issues then after replacement. I asked if it could be a wiring issues and they stated that it could be.
But the only way they could tell would be to pin out the complete wiring harness and see if there are any breaks in the lines. If there are breaks they suggested replacing the engine wiring harness. Isn't that big dollars for the harness and then the labor?

That was an expensive trip to the dealer last year! Yes, the fan relay is on the shroud and go ahead and replace that before your engine over heats.

I would never replace an engine harness unless there was a fire. You are correct, super expensive and will probably not fix the problem. You should ask to talk to an area representative as the mechanics are clueless, and the dealer no help. Write a letter to VCNA in New Jersey, nicely. Include a copy of the service done in 2014 as well as the current invoice.

And get a new oil cap seal, it is only $1.50 at the dealer.


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My back feels better when I sit in a Volvo seat

I replaced the fan relay last night as I have a couple more of them in my spare part inventory. Then I went ahead and cleaned up the oil spill around the neck of the oil fill area and directly south of that on the other side to what looks like a metal plug.
I also have been monitoring the oil daily to see if I'm leaking anything and the oil fill line is not moving at this point.
I am though monitoring a tranny fluid leak for which Volvo states that I'm leaking on the passenger side of the tranny where the Bevel Gear unit attaches.
Looking into what it will need for parts and time to fix. I might have to sub this out, but not at Volvo's hourly rate of $115/hour.