Engine Management Light On + Temperature Gauge Misreading = ?

[tjkennero]

Hi: Anyone got any ideas what's going on here?

I have a 2002 Leon 20VT Cupra. Yesterday the coolant temperature gauge started reading about 70 degrees on the motorway. Today the engine management light came on and the coolant temperature gauge read less than 60--again in the midst of lengthy drive. However, I was able to access the onboard ECU and read the coolant temperature digitally via the aircon LCD screen. Stays constant at 90. Yet EML light stays on. Car behaves fine and drives as before, so is this a false alarm or a sign of trouble round the corner. Any suggestions welcome.

TJ

[zollaf]

you need a fault code read. that will give you the fault that has triggered the eml.

[tjkennero]

you need a fault code read. that will give you the fault that has triggered the eml.

Thanks Zollaf: Using the same technique to access the ECU, the fault code was 0.0, which according to my information means that there is no fault!?! Hence, the puzzle thickens!!! Or should I be looking elsewhere for a fault code?

[zollaf]

you need a computer such as vcds. the em light is on, so there is a code. have a look in the vcds section here for someone local, or get a garage to do it.

[VWA]

Hi TJ

is your temp gauge still misreading? Not sure about the engine management light but it might just be that you need a new temp sensor. My 1.9 2002 tdi had a similar issue where the temp gauge would bob between 60-90 whenever it felt like it. The car would run fine though. Replaced the temperature sensor and its been fine since. You'll find the sensor on the right hand side of the engine (when your looking face on) , look for a plastic pipe that connects to the main engine body, this has several pipes connected to it, to the rear of it there is a dual outlet from what i remember, one for a pipe and one below it which houses the sensor.

Hope it helps.

[tjkennero]

Hi VWA,

Yes the gauge is still misreading. I took it to a nearby general mechanic who suspected and replaced the temp sensor. It then functioned fined for about a weak, after which the exact same problem arose again.

The fault code this time reads 17704 and I found two threads discussing this, one which suggests the next step is to replace the thermostat (a messy, time-consuming and expensive task) while the other suggests it may be a software problem. (The car was remapped by the previous owner).

Software problem: identifying non-existent sensor: http://www.seatcupra.net/forums/show....php?p=3224683

Thermostat problem: http://forums.vwvortex.com/showthrea...start-problems

The car is due a service in the next couple of weeks so I hope to get it looked at then. But I have also heard that the temp sensors are pretty iffy quality and that I might simply need another one ...

A bit exasperating if you ask me, but thanks for helping relieve some of the exasperation!

TJ

[VWA]

No Probs! Hope it gets sorted.