Wiring problems or something more serious?

Nov 17, 2022
My Seat has been off the road for almost 3 years and it's just had a cylinder head and head gasket repair which had no problems from the engine after it was done.

A couple of weeks ago I was driving it and the rev meter was taking maybe a couple of seconds to get to 1500rpm then the turbo kicked in which was fine. I was told to try replacing the exhaust temperature sensor by a mechanic friend of mine (who has 35 plus years experience). I did that now the engine revs as normal but doesn't go over 3000rpm, it goes into limp mode and stops the turbo from boosting and the coil light comes on giving me a warning.

The same mechanic tested 3 sensors around the engine - top left, bottom left and top right (I can't remember what they're called exactly - I have very basic knowledge of cars lol). So these 3 sensors/parts were tested with a voltage meter and each one was reading 3.7v which I'm not sure is correct. He used a device to draw more power directly from the battery to pass to the actuator and the turbo and they both started working as normal. When I drove the car with this device attached along with the mityvac it drove almost fine with the turbo boosting as normal but still not 100%.

The mechanic believes there must be a fault with the wiring somewhere because the error codes (EGR cooler switch over/Activation intake manifold runner control) I both stated "short circuit to ground".
I ended up buying one of those Haynes car manuals with the wiring diagrams to see if that could narrow down the wires we would need to check, it's still not arrived.

Has anyone ever experienced anything like this before?

Thanks in advance for your help.


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