2010 Rav4 Check engine light

Hi All,
The check engine light on my 2010 Rav 4 Ltd edition (170k miles in great shape) comes and goes. It seems to come on after a rain, cold or damp period. Then it will go off for no reason. Then back on–just in time for inspection. The code is P0607 ECM Control Module. So far I have checked the following:

  • Brand new battery, all connections good and clean.
  • just ran a ground from the neg side of the battery to where the control unit clamps–time will tell.
    Car is running fine but it does need an inspection.
    Wondering if anyone had any ideas or if this has happened to other Rav4 owners?

Check fuses and visually inspect cables to the ECM.

I hate to throw parts at a problem, but a used ECM doesn’t cost a fortune.

Thank you for the info—fuses and cables are all ok. Light came back on but appreciate the info about the ECM and will most likely replace and see what happens.


I’m skeptical about the ECM being the culprit. Aren’t most people saying that they are exceptionally reliable? Besides, I worry about opening up a whole can of worms if it is replaced, like won’t you have to reflash it to match your VIN and you might even have problems using your existing key?

I apologize for not having a better answer about what the real problem is. I have often heard that shops that are beyond their capabilities also give up and blame the ECM rather than performing a systematic diagnosis using the factory service manual (FSM). I think your funds would be better spent looking for a FSM on eBay or try out the online Toyota service manual site (I think it might be called TIS?). It might direct you to check specific points for voltages going into or out of the ECM and what other problems might give that code.

it’s not hard to find one of the companies who will take your own ECM and run it through the tests, repair only if needed and if they repair it, the VIN and key codes will be properly programmed into updated unit

I had an experience dealing with one such a company - I had to send my ECM by FedEx and then in a week they called me to inform that unit is 100% functional, so they charge me only 50% for diagnostics and send my unit back

sure enough, the problem was much more simple than ECM in the end, but required some more diagnostics

Where is your ECM located? Any chance rain is dripping/running down onto it or its connections?
Have you pulled the wire harness off of it to inspect the harness and ECM connections?

Thanks everyone for the info. I kept the car in the garage instead of the driveway for a few weeks because I know it must have something to do with the weather–damp and rainy. I drove it over 250 miles and check engine light did not reappear so it was successfully inspected. I discussed with the mechanic and he wasn’t familiar with that code. So, I guess all is ok until this time next year at inspection time.