Check engine light but no codes

[CaptainRedex]

Hi guys, got my (cheap) code reader today after hearing good reviews on it,

tested my car and it says there's no faults/codes even though I have a check engine light, is this due to my code reader just being a bag of s**t or does this mean something on a 9n 1.2?.. [emoji23]

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[bvs]

I had an EML light come on recently,and the code I got suggested a problem with the immobiliser,but the car was starting and running ok.
I have a couple of codes which keep reappearing but they are nothing important so I usually just reset them,one of them is AC related (AC does not work anyway LOL,rarely a problem in scotland ),but a couple of weeks ago I decided to check the AC fuses.Before I checked the fuses I ran a finger down all the fuses to check they were fully engaged - one of them was not fully engaged and I pushed it fully home.
The EML light went out without me resetting it LOL and (so far) has not reappeared.
I am not saying this is the cause of your problem but perhaps worth keeping in mind as an occasional check.

[CaptainRedex]

Thanks I had a guy come out with a VAGCOM system and not even that would get results so we check all the fuses and every was good, my OBD port must just be bust... Either way my engine light has gone out now after filling up my tank so now to wait for it to come back [emoji23]

Gonna have fun finding faults with a bust OBD port [emoji23]

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[bvs]

I must admit we sometimes drive for a couple of weeks with the EML glowing (as long as engine running ok of course) - our 02 9n used to throw a light up with monotonous regularity LOL,although I have gradually worked through the faults causing them.
But of course it is nice if you can confirm through OBD that nothing serious is going on,when I had a look at the fuse list I was surprised by how many fuses were related to the engine management system.

[RUM4MO]

I'm very surprised that a genuine and current version of VCDS is not reading stored codes when the MIL is illuminated, I've never ever heard or witnessed that.

What I have witnessed is a cheapie or basic OBD2/EOBD scan tool which is only designed to check/interpret engine emissions codes not picking up other engine fault codes, or VCDS being operated in OBD2 only mode incorrectly decoding a "manufacturer specific" code on a non VW Group car.

If the OBD2 port is faulty, your scan tool would/should have reported that being the case - and it did not.

[bvs]

That is the point I was making about the fuses Rum - the fuse I found not fully engaged was not visibly 'Sticking Out'/'Protruding' - I only found it by 'pushing in' all the fuses by hand,I am not 100% sure it was the 'loose' fuse which kept the EML on - it could just be coincidence that the EML went out afterwards.
I have seen the EML come on and then later extinguish itself (ie without resetting) if it was a very minor problem which the sensors were picking up.

[RUM4MO]

Any relevant fuse being O/C that was causing the MIL in illuminate would always log a fault code.

If the MIL comes on then sometime later goes off it simply means that the fault condition that caused that code to be logged has disappeared, normally with an older car, the original logged code(s) will remain held in memory until cleared or the battery removed/refitted, with later cars, certain fault codes tend to get esponged with time, so you need to check them quickly or lose finding out what they were.

[CaptainRedex]

The VAGCOM system just failed to connect, I had power going to the cable yet when we tryed to fun a scan it would just couldn't communicate with the system at all, couldn't even begin to scan for codes, very weird,

Either way my light has recently gone, I'm gonna have a go at testing all the pins on the OBD port to see if any are dead, of so check for lose or broken wires, this was the suggestion from the garage!

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