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Q: I have to actually use a heater on th ECU PROM to get my vehicle to start when its cold.

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It's a 1993 dodge ram D150 3.9 6 cylinder. Has 209,000 miles. I have to put a heater on the ECM PROM computer from 10 -20 minutes and than it starts to click and than once it stops clicking it will start. After it has been running a while it seems to be ok. When it sits depending on how cold it is it might not start again. Than you have to warm it up again.

Now if the weather is warm outside it appears to be ok and no problems with starting.

The other day it stopped completely and now it will not start. Before it stopped it was intermittent causing it to stall a couple of times. Now nothing at all. The engine does still turn over.

What do you think? Does the ECM PROM computer need replacing only? I have not tried warming it again.

My car has 209000 miles.
My car has an automatic transmission.

You have successfully diagnosed your truck. It definitely needs a new ECM. Electronics are very sensitive to temperature. There are relays inside the ECM box that you are heating, which makes the contacts expand and create an electrical connection. This will happen with relays, capacitors, resistors and all sorts of integrated circuits.

When it comes to replacing your ECM, make sure you have the old one removed and take it with you to the parts store. You should have your VIN number available as well. The old ECM will have serial numbers that will make sure you get the correct ECM for your truck.

This repair isn’t found in the inspection online, but most likely there will be a technician in your area that can replace it for you. I will have customer service contact you to help you out with this.

Thanks for your question.

Good luck!

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