1.8T having sudden sensor problems...help!

[Elcroato]

Hello,

I was beating the crap out of my 1.8T, remapped with Revo StgII, when I noticed the RPMs would continue to climb a bit after shifting. I then noticed the AC was dead.

I pulled over and ran a VAG-COM diagnostic. I have three sensor faults. Brake light switch faulty, oil pressure switch faulty, ambient temp sensor faulty. While testing, the coolant temp went up to 110C, the needle was 3 quarters over. The cooling fans kicked in at that point and lowered the temp back down to around 100C. My Climatronic has no power. I cycled the ignition. I reset the codes. Still no power. I tried disconnecting my MAF sensor and that fixed the RPM issues. The brake lights work fine. The fuses are good. Help!!!!!!! I live in Sicily and have no one that can understand me here.

Codes: 00562, 00667

[Bodge]

Brake light switch is a common issue. The switch has two functions, one is to turn the lights on (which obviously works for you) the other is to send a signal to the ECU/Sat nav every time you brake (the broken bit). Costs about £7 for a new switch and is a very easy job.

Ambient temp sensor is in the right hand side of the front bumper, you can see a little hole in the grille for it. Never heard of these going, but I guess it could have died.

Oil pressure switch is down by the oil filter, again never heard of these going.

Bit worrying about the water temp. Have you ever changed the water pump? Is the head gasket OK? Is it driving OK now, or is it still overheating?

Edited 22 September, 2008 by Bodge
i can't spell!

[ap0gee1978]

I had all sorts recently - disconnecting the battery sorted them all: linky

May not work, but it's got to be worth a try???

[Elcroato]

Thanks for the responses. I was away, hence the late reply.

I tried taking out the battery and checking the contacts as well as the grounds beneath it. No luck.

I changed my water pump at 100K km. Oil level and coolant are good. As I said, the temperature spiked at 110C at idle after this malady started which had me worried. The temp gauge needle hasn't risen past the mid-point since. This might be because every time I blow the ominous fuse #5(7.5A) I swap it out right way.

I've blown about 30 fuses already; testing. I have discovered that the car doesn't even have to be moving today. All I have to do is shift into 5th gear (not even letting out the clutch) and BOOM. This is with the engine off too mind you.

[rwbaldwin]

The ambient temp sensor may well be fed via F5.

It could be a bad flap motor.

Not sure about the 5th gear thing unless some cables are caught in the gearchange linkage at the gearbox end but I'm not sure how.

[Elcroato]

hmm, I'll look if the gear box is touching some cables while in fifth. Great suggestion. If that's not it then how does the car know it's in fifth? Is there some sensor in the shift linkage?

What did you mean by "bad flap motor"?

[rwbaldwin]

The flap motor is what controls the inflow of air in the heating/ventilation system (either from outside or recirc). If you can get the Climatronic to work, turn the recirc on and off a few times to test.

[Elcroato]

The Climatronic works just fine as well as the flap motor, until I blow the fuse.

[rwbaldwin]

F5 also runs to the door mirror switch.

Problems with the wiring loom from the driver's door where it passes through the 'A' pillar are common.

Open the drivers door and 'manhandle' the wiring loom as it passes from the door to the 'A' pillar. See if the fuse blows. The key must be in accessory/ignition position as F5 has no voltage when in the off position.

[Elcroato]

Sounds like a good idea. Fortunately I won't need to pursue this problem further as I figured out what was wrong!

The "weighted" part on top of the tranny(O2J) was rubbing against a huge wire bundle that ran from underneath the battery to connectors under the intake manifold. One wire in the bundle was exposed from the constant friction. I patched the exposed wire and moved the bundle. The short is gone!

I'm so happy I fixed this. I can enjoy my beloved underestimated Skoda once again! Thank you for your replies Rwbaldin and everyone else as well.