I took Clay's Jeep into the shop yesterday to have the codes read. All that is showing is A/C relay and fan relay. A/C is disconnected... have to figure out how to fool the ECM on that one. Have not yet figured out the fan problem.
I swapped a 92 4.0 into my cj. It throws both those codes at all times.
I don't have an AC and my fans are a separate electric set up, so I never paid it any mind.
Not sure how you would fool the computer to stop throwing those codes, but if you find out, I'd be interested in what you did.
I'm no expert on FI or AC systems, I do wonder if the pressure switch in the AC Refrigerant line has any thing to do with the code. IF I'm correct on this, the refrigerant is under constant pressure, even when the engine isn't running, so the computer see's a lack of pressure and throws the code if the switch/wires aren't hooked up to a source of pressure.
So either a source of pressure would be needed for a sensor reading, or figure out how the switch functions, and create the Scenario.
I don't think oil pressure at idle would be enough pressure, fuel pressure on a FI engine might be. Or, if you had OBA the sensor could be placed there.
These are just some random thoughts, I have no clue if this actually throws a code. Might be worth looking into at any rate.
I wonder if you can't just twist the wires together??
The A/C has two failsafe switches built into the pressure system. One for high pressure (> 500psi) and one for low pressure (< 25psi). Both these switches need to be closed in order for the A/C clutch relay to be activated. This is easy to fake by simply twisting the wires together, effectively shorting your (non-existent) switch. However, having these wires not connected should not throw a code, since the circuit is designed to only be closed when the AC is on.
I suspect that the code is being activated by a diagnostic self-check on the AC clutch relay. The relay is basically an electromagnet that pulls a high amp contactor closed when a current is passed through it. As such, there should be a constant resistance across the coil that can be checked by the computer to ensure that the relay is intact and able to function. If that resistance is not there, the computer MAY set a code. I'm not sure about this, but it makes sense to me.
So, to fool the computer, you need to put a resistor from switched 12V to pin 34 on your ECM. First measure the resistance across terminals 85 and 86 of a relay, so you get the right size resistor.