Engine/Transmission (1998.5 - 2002) have multi-meter can i test APPS

[MCharlebois]

any info would help??

thanks

 

[15w40]

I will try to describe how I would check the APPS using a multi-meter. First maybe a description on what is what on the 5-pin APPS connector.



Pins 1, 2, and 6 go to the idle validation switch. This switch has a normally open contact, pin 2 and a normally closed contact, pin 6. Pin 1 is the common switch connection.



With the throttle not pressed you should see close to zero ohm between pins 1 and 6. Between pins 1 and 2 you should measure infinity.



With the throttle floored you should see zero ohm between pins 1 and 2. Between pins 1 and 6 you should measure infinity.



The accelerator position part of this comes out on pins 3, 4, and 5. Think of this as a potentiometer where pin 3 is the wiper and pins 4 and 5 are the end points of the pot.



Between pin 5 and 4 you should read 2000 ohm to 3000 ohm.

Between pin 5 and 3 you should read 1500 ohm to 3000 ohm with the pedal released.

Between pin 5 and 3 you should read 200 ohm to 1500 ohm. with the pedal floored.



Released resistance minus floored resistance must be 1000 ohm. Also when measuring between pins 5 and 3 the resistance should fall steadily with no glitches as you depress the throttle.



And one last thing, when the APPS is connected to the ECM, pin 5 should be at 5 plus/minus 0. 25 volts with respect to pin 4. This voltage is generated within the ECM.