Check Engine Light Shenanigans.

[Reedy]

So my check engine light has been fairly well documented but I have had a further development today, basically the CEL light has gone, as in doesn't light up anymore, but when checking the ECU with my OBD scanner the P2096 code still exists in the ECU.

Things to point out:
1. I went to the track the other day, today is the first time i've driven it since.
2. The globe is fine, it comes on when the car is started like all other lights do.
3. What the fk?

I will drive around for a few more days and see what happens. If the light stays off then I will clear the code from the ECU and see if it reoccurs. Previously if I cleared it then it would come back on again within about 5 minutes of driving. But the light turning off without any intervention from me is strange indeed.

[Oldhead]

Hey Reedy , I too have same issue and i have traced it back to the possible factor that u gave the car a good blat at the track!!!
U heated up the rear 02 sensor and cleaned it of carbon build up.
This happens to me on a regular basis , noted it the first time i gave the car a good clean out via right foot.
Exact same issues, dash engine light (P2096) stays on (can clear with dashawk ) comes back after some normal driving , But if i give the car a good thump ,watch the plumes of black smoke out the exhaust,then sometimes the check light disappears for several days ????? . Bloody ECU /Dump pipe.
My dump has second sensor at OEM position ,inserted at 45 degree and 100 cat positioned further along DP not b4 the sensor.
Seems a logical answer as i have also monitored the Millivolts to sensor during these occasions and noted a rise in volts during spirited driving.

[Reedy]

Yea well I cleared the code today and drove 100k's and it hasn't come back.

The thing is tho, ive been to several track days with the CEL on in the last few months and they have never changed anything. The P0421 code actually came on during the drive back home from Queensland Raceway and that's what started this whole saga!

It's funny, at my next service I was going to request that they clean my O2 sensor as I had long since suspected it had become fouled. Especially since I had the O2 sensor bung removed and the P2096 still persisted.

Will wait and see what happens over the next week or so I guess!

[toine888]

I've had the P0421 cel for the last week. Its happened last when my coil packs blew and caused o2 sensors to blow also. I hope my o2 sensors are ok and they just newest a clean. Is this a common cel code which comes on with heavy right foot syndrome?

[3MPSPWR]

Hey this has also happened to me before. I've been getting the P0421 for awhile now - ? Anyways, i've been clearing it just cause it annoys the shit outta me but about 2 days ago it came back on and i left it and today it's gone? I do think it will come back though, not too sure what it could be exactly. I do find with mine, it occurs after a "long drive" on highway cruise speed that it throws off the CEL. If i clear it and drive it day to day it doesn't usually come back. Strange one...

[Reedy]

I've had the P0421 cel for the last week. Its happened last when my coil packs blew and caused o2 sensors to blow also. I hope my o2 sensors are ok and they just newest a clean. Is this a common cel code which comes on with heavy right foot syndrome?

It's a common code for Gen II ownders with aftermarket DP's. It's uncommon in Gen I's from what I hear but still quite harmless, altho your coil pack issues could be causing problems.

[Nirvandan]

Option 3 for me lol

[Reedy]

Still no CEL anywhere to be seen.

[2XS]

The turbos failed on the Gen 1 on cars that were driven in heavy traffic.
Seems like the CEL issue could be from the same type of issue.

Drive it hard, drive it often, live life in the fast lane (and possibly CEL free)

[toine888]

Yeah I'm sure its nothing. Its actually off now and has been for a week. So all good

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