DME Voltage Drop

[tcoradeschi]

There are a couple of basics to check - perhaps you have already done these. First thing would be to check the grounding of the DME. See if there is any voltage between it and the negative terminal on the battery? Other than that, trace the 12V line back to the fuse, checking voltage at every connection you can find.

One quick-n-dirty check would be to run dedicated 12V from the battery to the DME to see what you see.

[Danimal]

I am having issues with my locks randomly not working. I checked the immobilizer and there is no corrosion. And changed the passenger door lock actuator, no change.

The locks will usually work in the morning or the first 30ish minutes of driving. Then when the car gets warm or after it’s over or under charged they no longer work. My charging system also reads 14 something at the battery and 13 something per the dme. So I’m wondering if I also have a voltage issue somewhere. Possibly to my immobilizer. My car also chugs a bit with the ac on at idle.

Please keep us posted on what you find.

[Lacostas]

Originally Posted by Danimal

I am having issues with my locks randomly not working. I checked the immobilizer and there is no corrosion. And changed the passenger door lock actuator, no change.

The locks will usually work in the morning or the first 30ish minutes of driving. Then when the car gets warm or after it’s over or under charged they no longer work. My charging system also reads 14 something at the battery and 13 something per the dme. So I’m wondering if I also have a voltage issue somewhere. Possibly to my immobilizer. My car also chugs a bit with the ac on at idle.

Please keep us posted on what you find.

As a first step its good to replace both DME relays (in trunk) and see if it helps. Cost me like 7 EUR each. Then maybe try to measure the voltage on those relays and check where the drop happens and if voltage reaches them intact or lower.

[Lacostas]

Originally Posted by tcoradeschi

There are a couple of basics to check - perhaps you have already done these. First thing would be to check the grounding of the DME. See if there is any voltage between it and the negative terminal on the battery? Other than that, trace the 12V line back to the fuse, checking voltage at every connection you can find.

One quick-n-dirty check would be to run dedicated 12V from the battery to the DME to see what you see.

Thanks for the input - already tested the ground (i used jumper from ECU ground to battery ground and the voltage was still much lower than the battery).

Im thinking to somehow do the quick-dirty check but im afraid to do it without a fuse in between ..

Maybe i can find somewhere such a fused jumper cable to connect battery all the way back to the DME Relay's (both of them) and recheck DME voltage. Oh by the way both DME relays (PIN 30) showing the same DROP in voltage so i assume it may be something between the fuse box and back.