I modified my ECM because of an intermittent AC request input signal.
Car had a horrific surge at idle - half throttle. Anytime the ac clutch permissives were met. (Low pressure switch, low enough TPS, etc.)
Even with the switch in the OFF position in the climate control! this would happen. With a Digital multimeter measuring to ground I could not reproduce the error. Because even the internal resistance of the DMM was sufficient to "pull down" the voltage that was triggering the input. I solved this by soldering a 20k ohm SMD resistor on top of the cap that connects the input to the ECM's ground plain. you can see in the image I've marked the cap in blue. This is pinned to the light blue wire that is the AC request wire in the harness. No issue since....
Car had a horrific surge at idle - half throttle. Anytime the ac clutch permissives were met. (Low pressure switch, low enough TPS, etc.)
Even with the switch in the OFF position in the climate control! this would happen. With a Digital multimeter measuring to ground I could not reproduce the error. Because even the internal resistance of the DMM was sufficient to "pull down" the voltage that was triggering the input. I solved this by soldering a 20k ohm SMD resistor on top of the cap that connects the input to the ECM's ground plain. you can see in the image I've marked the cap in blue. This is pinned to the light blue wire that is the AC request wire in the harness. No issue since....
