P1607 Engine Control Module (ECM)/Powertrain Control Module (PCM) Internal Circuit Malfunction.

I have tried switching PCM's/Clearing codes but its still showing up. What else should I try?

 

i should charge you for this info, but ill be nice. aquire the appropriate pinout diagram for your ecu's plugs. then proceed to verify each of the ecu's power wires have the correct voltage. then proceed to perform a continuity test on all ecu grounds. this means checking voltage from the ecu plug to the ground location that the wire goes to. you should find your problem somewhere within there if you have already swapped out with a KNOWN GOOD ecu.

 

right on bro, thanks!

 

^^^ this will most likely find your problem, but I wanted to throw in something less likely, but possible.

What engine/ecu are you using? OBD2b gsr ECUs, and I think some OBD2b type R and H22 Prelude ECUs will throw this code if they had the immobilizer removed... which is necessary if you want to run an OBD2b engine and 2b ECU.

Mine throws this code because I removed the immobilizer in order to put a 2b gsr engine in a 2b car and keep the 2b ecu and harness. No limp mode, just P1607 code. If that's the case, you have a few options...

 

yeah its not in limp mode and it is running the obd2b gsr ecu. Right on! thanks bro.

 

There's your answer. As far as I know, all 2b gsr ecus had the immobilizer. Unless it's removed, the ecu won't start an engine outside of the car that it (the ecu) came out of.

So, if you have a 2b gsr ecu, and it's running fine but throwing the P1607, it's had the immobilizer removed.

H-T user Katman (I think) has a service where you send him your ecu and he can solder in a dummy chip in place of the immobilizer that gets rid of the 1607 code. Last I checked, it was $100. I haven't done this on mine yet, so I can't comment on it.