Hello there, my brother recently got a Seat Leon Cupra MK1 1.9TDI with a PD150ARL engine and his Mass Air Flow Sensor has a live brown wire from the sensor to the live battery terminal. If not attached to the battery it kills the battery, runs rough and takes time to start even in moderate temperatures. But, when attached to the battery it runs as it should. No one knows what the issue is and how to fix this, he is running out of options and is debating selling the car. However, it is his second car in less than a year as the previous one, that being a Skoda Fabia VRS, and that one had issues too and i would like him to enjoy the Seat he has now instead of worrying about this issue. We will appreciate any and all help. Thank you for reading and taking your time to help.
Live MAF sensor.
- Thread starter AMorrison00
- Start date
Does it have a bad earth or something and the previous owner has cobbled some sort of workaround?
Hi mate. Hard to say with certainty without looking at it, but it sounds like there is probably a break or a short circuit in the wiring harness, on the 12v supply to the MAF. Rather than mess around ripping open all the harness to find the break, it sounds like some has just run a wire straight from the battery to the 12V pin on the MAF. If that's the case, then obviously the best thing to do would be to find the break and repair it.,
The current bypass is ok as a bodge, but only as long as the wire can't catch on anything, and there MUST be a fuse as close to the battery end of the cable as possible. A 5 or 10 Amp fuse should be fine and you can buy inline fuse holders on ebay or at halfords.
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