Just thought I'd post this on here, as I never found it before when doing a search, and had to go to NASIOC to get it:

Home made fix for the Catalyst Efficiency CEL code (0420 IIRC?) on the bugeyes:
Go to rear 02 sensor - there are four wires, two black, a white and a blue. Leave black wires alone - they supply power to the heating element. Insert 1Megaohm 0.5Watt resistor in white wire. Solder 1 microfarad tantulum capacitor across the blue and white wires (-ve end to white wire). Best to do it near the multiplug for the wire to the sensor. Total cost of components - 26 pence from Maplin (cheaper than most bought in CEL fixes)

Decided it would be cheaper and faster for me to do this than go and get my Ecutek map updated to turn the light off. Have been running it for about 1000 miles, a lot on the motorway, and have had no recurrence of the light, which previously would come on quite quickly, so seems to work nicely.

The other standard CEL fix (that I've not tried) is for the up-pipe EGT probe - if this fails, disconnect the multiplug, and put a 2.2 kOhm resistor pushed into the two wires of the multiplug. Something to note here - this does override a safety check, decidedly unadvisable if you have an up-pipe cat still in place.

hades, i can tell you that this fix works perfectly.

i chose to strap it into the harness right near the ECU. it sees less weather and i am handy with a soldering kit.

if you do it there, the wire colors become reversed... white-->blue and vice versa.


hth
ken

Good lad.

Just replaced mine. :D

Maybe next time, Ill save my self a few bob.