My car idle speed actuator connector has 3 pins. Disconnected the plug from the actuator, and key at on position, and each pins are individually grounded with multimeter, the multimeter reads 12.60 v for the 2 pin, about 1.56 volts each for 1 and 3 pins. Surprise, why pins 2 and 3 are giving voltage reading. Shouldn't they give 0 volts???
1 Answer
I got this from a 1.6 liter Hyundai manual (we don't have the 1.2 in the USA) but the operation is exactly the same.
The voltage you are seeing is probably the result of a "pull-up" resistor on the grounding transistors inside the ECU.
-
-
@ThangTons Yes, completely normal. It biases the transistor so that it does not have a path to ground unless energized. As a result, it creates a "phantom" voltage on those two signal lines when not active. Jul 1, 2019 at 22:51
-
But why the rpm still at 650 from normal 850 after having cleaned the TB unit, ISCV??? Also, I try resetting the computer memory by disconnecting the battery and reconnect after 15 minutes. Still then, no change. Still 650!!! Please kindly advise. Thanks. Jul 2, 2019 at 2:44
-
I would check and clean the ISCV and make sure the Throttle Position Sensor (TPS) is adjusted correctly. Jul 2, 2019 at 2:52
-
Yes, have done all cleaning including iscv, TB unit etc etc... still 650 rpm Jul 2, 2019 at 3:02