you can not use ohms (DMM resistance) with a live circuit. any voltage present will cause any ohm meter to go quite nuts.
and key off the power feed, is open so you will read nothing, but leakages.
you could measure ohms key off from the a13 pin VIO-yell. to the fuse marked IG coil, this is the black-white wire there,, and will read zero ohms because the filament is a dead short and low voltage power inside the ohm meter.
the fsm way works best because it makes the lamp glow.
using and ohm meter test is not 100% accurate, with a double failure, say lamp is out and there is short to ground on that wire. but I'd bet not. but.
yes, if the fed mileage nag switch is still in place and wired, it must glow the CEL in one of the 2 positions. this too is a good test of the lamp.
i remove all nag switches, i see... and other do to, so this is not a reliable method to check the CEL.
here is the CEL in ASCII art?
12v >>>>> xxxxxxxlamp>>>>> ECU >>>> transistor>>>> ground. (if anything breaks this serial path of conduction the lamp is dead.
Usually if the caps in the ECU are good, the top right portion works perfectly.
this is the path for the light. the lamp is a top failure, as it only lasts 700 hours. some folks drive with it on (code 51) and it about 1 year on average.
and key off the power feed, is open so you will read nothing, but leakages.
you could measure ohms key off from the a13 pin VIO-yell. to the fuse marked IG coil, this is the black-white wire there,, and will read zero ohms because the filament is a dead short and low voltage power inside the ohm meter.
the fsm way works best because it makes the lamp glow.
using and ohm meter test is not 100% accurate, with a double failure, say lamp is out and there is short to ground on that wire. but I'd bet not. but.
yes, if the fed mileage nag switch is still in place and wired, it must glow the CEL in one of the 2 positions. this too is a good test of the lamp.
i remove all nag switches, i see... and other do to, so this is not a reliable method to check the CEL.
here is the CEL in ASCII art?
12v >>>>> xxxxxxxlamp>>>>> ECU >>>> transistor>>>> ground. (if anything breaks this serial path of conduction the lamp is dead.
Usually if the caps in the ECU are good, the top right portion works perfectly.
this is the path for the light. the lamp is a top failure, as it only lasts 700 hours. some folks drive with it on (code 51) and it about 1 year on average.
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