Quote:
Originally Posted by ard
ALSO!! you may not find a solid short just ohm-ing things. There MAY be a circuit that isnt ';active' until the car is powered on, but once powered on the circuit closes and then a bad sensor/.actuator causes the short/fuse blow. Odd but possible. Look at this:
https://www.newtis.info/tisv2/a/en/e...lation/cuMAnjp
See the 20A supply from F02 goes to the pre-heater in the o2 sensor. The DME actually 'controls' this by grounding the other end of it at pin 3. When the car is off, pin3 is not grounded- it is only when the DME is on and decides to run the preheat that it grounds that line. At which point the pre-heater then pulls current through F02. if that o2 is bad it would then pop the fuse. My point is that static checking might be confusing at first (hence I posted all the little 'sub-diagrams' above)| |
In this case we are measuring resistance of the voltage supply lines (from F02) against solid ground point (resistance of the supply wire and end device). So it won't matter (for the measured resistance) what the vehicle does on the ground side when it's activated.