My '96 Discovery failed a recent emission test in WA State. OBDII test type. The fault code was:

P0158 O2 Sensor Circuit High Voltage Bank 2 Sensor 2

My regular (non-dealer) mechanic recommended that we replace the rear O2 sensors, which we did (purchased from Rovaguy.)

A day later, the Check Engine light came back on. Mechanic said that he had reached the end of his ability to diagnose Land Rover emissions problems. :-(

I took the vehicle to a Certified Emissions Center (European Motorsports). They received the following fault codes:

P0430 Catalyst System Bank 2: Efficiency Below Threshold
P0420 Catalyst System Bank 1: Efficiency Below Threshold

That mechanic thinks it may be a bad catalytic converter and said that he could replace them (2?) with OEM parts that will run over $2,000. That's more than my vehicle is worth. He told me that Discoveries have problems with non-OEM catalytic converters.

Does his diagnosis make sense?

My tabs are expired. The 'Rover is my only vehicle. I can't spend more money to fix it than it's worth (I just put over $800 into it for brakes and master cylinder... a whole OTHER story).

I'd appreciate any insight and advice from the forum members.

Thanks, folks.

 

At the indy repair shop I worked at until end of day today (no more ******* owner for me!) we have performed a BG induction cleaning on the last 4 vehicles that have P0420 codes. One vehicle had the induction service done twice (after the code returned). On all vehicles, the code has not returned within ~1,000 miles after the first (or second) cleaning.

IIRC, the service ran about $140, which is far cheaper than a new converter. Prior to finding the good results of the induction cleaning, we would get used converters from Brown Recycling Mfg., Inc..