2005 Golf 1.9 TDI Emission warning light

[shelto]

Hi
My emission warning light came on whilst driving home from work. I popped into the local garage who put a diagnostic computer on. The diagnostics came up with 'Fuel Temp Sensor shorted'. This has since been replaced, however after about 10 miles/ 3 starts the light has come back on again. The local garage said bring it back and he'll have another look at the fault codes thru the computer but i may have to take it to a dealer which is going to be expensive. Has anyone had similar problems?

[Crasher]

I am not sure why taking it to the dealer is necessarily going to be expensive, if it is a broken wire and not a faulty sensor, taking it there in the first place may have ultimately been cheaper. The fuel temperature sender fault code is very common but sometimes it is the sender, sometimes it is the wiring. Take it back to the original garage and get them to code read it again. If it is the same code and the sensor has definitely been replaced, then it is probably a broken wire but may even be the new sensor is faulty, it is not unheard of.

[shelto]

Cheers for the info, much appreciated. I've been reading other forums and they've been talking about lambda sensors and EGR's causing the same fault, also saying its not as straight forward as it looks as these were changed and a couple of days later the light came on again, thats why I was worried about it getting expensive.

[Crasher]

Don’t listen to people trying to scare you, the first thing to do is have another code read to see what has brought the light on.

[shelto]

The story so far; took it to a vw specialist who put it on the computer to check the fault codes - thrust sensor fault and altitude (i think) codes came up. They changed the thrust sensor and the fault code cleared but the other fault is still present, or only appears when the engine is rev'd, they seem to think one of the hoses could be leaking. It goes back in tomorrow to have them checked out (they checked the top hoses which seemed ok but want to put it on the ramp to have a proper look). I'll be glad when its sorted because its gone into 'limp home' mode and has as much power as a 1litre Corsa.

[Crasher]

Insist on a code print out, it is impossible for us to help you without knowing the VAG code number.

[shelto]

Will get the code read out tomorrow. The car has been with them all day turns out its still a fault with the thrust sensor even though its been changed, something about lack of boost pressure. They thought it might be an airleak causing it, however they've checked all the hoses and cant find anything, apparently the fault is there even when the car is not running. They're now saying it could be a wiring fault or the ecu, which they've quoted at roughly 1000 pounds to change all in, I cant believe it could be changed and the fault still be there and a grand down the swannee. They're going to check the wiring tomorrow but to be honest i dont think they're pinning their hopes on it. Will keep you posted.

[Crasher]

Here we go, blame the ECU, the resort of the clueless-usually. I have a method I follow that serves me well, “It is never the ECU, in about 99% of cases and it is never wiring in about 90% of cases”, especially on a car of that age. They are missing something but I need those code numbers or I am guessing and I don’t like guessing.

[shelto]

Just thought I'd let everyone know the outcome and hopefully end of the saga.
The fault code was 18000/P1592/005522 - Altitude Sensor/Boost pressure sensor: Implausible Correlation. The guys buzzed the loom thru but didnt get continuity from the wire coming from the boost sensor, further investigation revealed the wire loom had been rubbing against the gear box and the wire concerned had rubbed thru and broken. They have repaired the wire and routed the loom away from the gear box. I've driven the car home and so far so good, although it does seem to take a few more turns of the engine to get it started.

[Crasher]

So it was wiring then.