UK Car Repair: Vauxhall Corsa, vauxhall corsa, diagnostic port

Question
QUESTION: I have a Vauxhall Corsa 1.3 CDTI SXI on a 53 plate. The problem I have at the moment is there is a light on my dashboard which keeps coming on, its a car with a spanner going through it.  This light has been coming on and off now for the best part of 12 months. It will come on every time I drive for a few weeks, then it wont show itself at all again for a few weeks. The manual says it could be the fuel filter, which has been changed, or it could be the engine electronics, which sounds expensive! I have also been told that because sometimes it comes on and sometimes it doesnt that it could be just a loose wire or something.  It doesnt seem to effect the car at all when Im driving, but I would like to sell the car and dont want it popping up when someone is test driving it, at the same time I also dont want to be taking it to a garage and spending a fortune if it is the engine electronics. Help please

ANSWER: You need to go to a parts store such as carlines, they can use a scanner connected to the diagnostic port of the car and tell you exactly what cods come up - more than likely it will be a sensor of some type or a bad sparkplug, nothing too expensive -
, it should not be expensive and some places will do it for free, phone local parts shops and see if they will "scan the E.C.U."
Pretty sure halfrauds have been known to do it for free but some charge £29.99 which is "unfair".

When you get the error code(s) tell me what it (they)is (are) E.G Error code: 0012, 1110, etc...
(don't let anyone start presuming and changing parts, I've had so many people think because the fuel pressure is low on the sensor, the sensor was at fault, when in fact the fuel line was blocked... so tell me what codes it comes up with and i'll diagnose it myself.)


I suspect a slightly dirty injector, or maybe some soot build up, if that is the case the "old-way" to do it was put £20 diesel and £2 petrol (minimum petrol you can buy at some pumps)in a nearly empty tank and push the engine hard for a good few miles, clears the soot and cleans the fuel system from top to bottom.



---------- FOLLOW-UP ----------

QUESTION: Ok I have had the E.C.U. scanned today and it showed no errors at all, halfords couldnt do it but a local garage did do it for a tenner.

Answer
That's surprising.
-  with no error codes and an intermittent warning light...

You may have to have vauxhall themselves look at this -

Let me do some research on this car see if the problem has come up before -

, though I think maybe the fuel lines are a little clogged up since this light is related to fuel filter / sediment -

I'll get back to you.

---

There must be a fault - the light means "problem encountered, bring car back to vauxhall"

- you could try something like this >>>

http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogI

It may or may not solve the problem, but it;s worth a shot.

--- otherwise it will have to be a bone fide vauxhall dealer who diagnoses the fault.


<<<<<<<<<The thing is the light that comes on is the engine management/fault indicator light, if it lights a code is written to the ECU, the mechanic must have missed something out or used the wrong scanner or something because there absolutlely must be an error code on the computer after the light has been on. so a scan at vauxhall seems the only way forward>>>>>>>>>>

I mean if that doesn't show a fault code then the ECU itself is at fault, that light should only come on when an error is encountered, and any encountered error is recorded on the computer...