I have done a bunch of searching and cannot find anything that is specific to the issue that I am having. I am experiencing a P1510 CEL. I did head gaskets on the truck and the code did not exist prior to the maintenance. So its something that I touched or affected somehow.

Vehicle:
2001 Disco 2 with 4.6L petrol engine

Here is what I know:
"P1510 IACV opening coil malfunction, short circuit to battery supply"
The engine idles low and poorly when the CEL is illuminated
The tach does not function when the CEL is illuminated
If I clear the CEL (P1510 is the only codes) the idle comes up and the tach begins to function. The truck runs and drives normal when the CEL is turned off. The CEL returns when the truck is turned off and restarted.

This is the troubleshooting that I've done:
-Battery voltage and amperage is fine. The truck has two new batteries in a dual battery system that are being combined during start up to ensure enough voltage is provided. I have also started the truck with a battery charger set to 200amp just to ensure there was more than enough voltage to start the car and eliminate the batteries as a source for the issue.
-All engine and chassis grounds have been checked and cleaned,
-a known good IACV has been installed
-I replaced the Crank position sensor with a new one, just in case it was not providing signal to the computer, preventing the computer from sending proper voltage to the IACV.
-I have read the signal wire going to the IACV and it is not receiving the proper 12v to cycle the IACV to the open position, the closed position circuit is getting the proper 12v on occasion when it is trying to control the closed circuit.
-I have jumped the open circuit signal wire with 12v battery voltage near the IACV and the valve functions as you would expect.
-I have jumped 12v battery voltage at the ECU connector at pin 42 and received 12v at the valve connector and had the valve cycle, so the wiring/connector between the ECU and the IACV is not an issue.
-I have checked continuity between the eco pin 42 and the IACV connector and there is continuity.

My thoughts on what might be the problem from here:
-Is the ECU bad?
The connector for the Crank Position Sensor never has had a positive feel to it, previous owner maintenance broke off the locking clip between the wiring harness and the CPS. The connector is help together with a zip tie. My theory, if this wiring harness or connector is not optimum it could be sending a poor crank signal on start up and causing the issue I'm experiencing. I have a repair wiring harness that I can swap in, but I have to remove the upper intake manifold to do the repair, doable, but if there is something else that may be the issue i would rather go after that.

Thought? I feel like I have done a pretty amount of troubleshooting, I have just reached a dead end.

Thanks.

 

Never heard of the IACV driver in the ECU going bad, but I guess it is possible. I have several ECU/BCU pairs, if you wanted to try one I could ship it to you. I would double check your wires to the IACV - known issue that the insulation gets brittle.

 

Yep I'd inspect the wiring as well.

I had a rather small flash fire in my engine bay after I cleaned under the hood of my 02 Kalahari after the 2018 HCRR. I used a different product than I normally do to clean under the hood and apparently it got onto my drivers side exhaust manifold. I cranked my D2 to move it, popped the hood to check something and WOOOSH as soon as the hood raised I had a brief 5-8 second flash fire!!!!! It went out and I didn't see any damage. I had a crazy P1668 fault right after it, and the TC/HDC light came on. That stopped, but now I instantly get a P0130 for Bank 1 Upstream O2 sensor, so I'm guessing my harness to the O2 sensor got a little toasted. Of coarse you can't see very well back there so I'll have to remove the upper intake to fully inspect it. I tried moving the O2 sensor to the other bank, and the problem stays with Bank 1 Upstream sensor. Sucks big time as I was just trying to be nice and keep her clean under the hood after all that nasty dust/dirt/mud. Next time ummm nah it can stay gross lol.

 

Update:

The issue has been fixed. Thanks for the advice. What I found was a broken "12v open" wire about 6" from the IACV. I just ran a new wire from the ECU pin 42 to the IACV and all of the issues have resolved themselves.

Cheers,