Technical EML on without error code

[brinker]

So my EML just came on this morning, after about 5 minutes of driving. I had just been at a stop, as I needed to pull out onto another road, when it turned on. The car was then turned off at the petrol station and once I got to work. I scanned it 10 minutes ago with MES, no code. Tried starting the car - EML still on, but no code registered. Where do I start? There's no noticeable difference in driving at all.
How do I clear the light when there's no code to delete? Disconnect battery for 10 minutes?

 

[s and b]

weird

 

[dtimmins1985]

Could be an electrical issue... have you tested other modules on mes to see its all working fine?

 

[g8rpi]

What engine?

 

[g8rpi]

If you connect to the ECU with MES you can turm the failure light on and off from the "Actuators" tab (F6). This will at least rule out a failure in the light electronics or wiring.

Robert G8RPI

 

[brinker]

1.2 8v. I'll try have a look at the actuators tomorrow.

 

[brinker]

So I have now tried with both my ELM327 and VAG KKL, to activate the EML in the dash - both times it said "Failed to execute". Just started my car, and it's now revving 2000-4000rpm by itself... I have literally only done the above.
I have disconnected the battery just now, to try and see if this clears it.

EDIT: Battery reconnected and car no longer revs by itself. However the EML is still on...

 

[g8rpi]

Hi,
You need to check the battery and engine earth leads, ECU mounting earth and ECU connectors for corrosion or loose connections. Have a good look at other connectors and wiring looms for water,ingress chafing or other damage.

Robert G8RPI.

 

[brinker]

Thanks Robert. I'll have a look around the engine bay. Not sure I'll get around to it before Friday, but we'll see. Will keep you posted.

 

[dtimmins1985]

Sounds like you didnt get a connection to the ecu with your cables...

Have you set the latency correctly in windows, are you using latest drivers for the ftdi chip / usb serial port.

 

[brinker]

If it didn't connect, it would tell me it didn't connect. It connects just fine, and all parameters are working. I've been using this setup with my ELM cable for several years now, without any issues - and have previously read out error codes and cleared engine lights on this.

 

[brinker]

I went through connecters and wiring yesterday, everything looked fine. Removed and cleaned throttle body (as I hadn't done so for a while), wire brushed surface betwwen TB and ECU. Let engine idle and went out into engine bay and moved around connectors and wiring to see if it would trip anything - but just kept going like nothing happened.

A colleague of mine will bring his test equipment tomorrow, hope maybe this shows an error code, but I kinda doubt it by now...

Additional info: Battery voltage ACC 12.1V - Battery voltage ON 13.6V

 

[brinker]

My colleagues test equipment showed a stored P0130 (Lambda 1 circuit malfunction). I've deleted it for now and my EML is off again. Hopefully doesn't come back - otherwise my O2 sensors are only 8 months old, so should be covered by warranty.