CE Light & Catalytic Converters

[dbear61]

Here’s a CEL puzzle on my 2001 Boxster S.

Last Summer, I was on a road trip through New England, and the CEL stayed on at start-up. Two stops later, the CEL is off at start-up. Three stops later, the CEL stayed on at start-up.

I continue the drive home with CEL constantly on. Back in WI, my local dealership analyzes the problem, and comes back with both catalytic converters need to be replaced. Pre-cat and post-cat sensors have the same readings. Quote is almost $7,000. That is not happening.

I had both cats replaced with after-market parts in 2016. For both to fail simultaneously? At the time this showed up, it was only six years, and probably about 30,000 miles. That doesn’t make sense to me.

I go back to my independent who did the replacement. “I’ll have to look into it.” A month later, the weather is starting to turn, so I just take the car home and store it for the Winter.

In April, I bring the car out of hibernation, and the CEL turns off after ignition. WTH? I drive about 150 miles around town in 5 or six trips, and it is still off. I stop at the dealer, and they claim it takes a while for the OBD to reset after being in hibernation (never took this long in the prior 10 years).

I go on my Route 66 road trip. Interstate, city, country, start, stop, high revs in each gear, low revs in each gear, low altitude, high altitude. The CEL is off the entire time. Then, 12 days and 3,200 miles into this varied-conditions trip, the CEL comes on at ignition.

Three days and 2,000 miles later, the CEL is still on. My friend has an OBD monitor with him, so he plugs it in, and it returns a code for Bank 1 catalytic converter not performing properly (I wish we had done this at the start of the tip to see if the OBD was active). Only Cat 1. He resets the OBD, and we finish our trip over 400 miles with multiple stops, driving conditions and temperatures. The CEL is still off. I do two local, five-mile drives, and it is still off.

I go to the dealer, and the service manager still thinks both cats are bad, that I haven’t driven enough conditions for the OBD to reset and recognize that both cats are bad.

I just do not think their conclusion is plausible. How do both cats, even if after-market, fail simultaneously after 6 years and only 30,000 miles without any Winter driving? Even if the OBD resets during storage, how do you drive 3,200 miles in multiple conditions before the OBD wakes up and sees something wrong?

I think there’s something wrong with the OBD, but my dealership is adamant that it is working, and I need to replace the cats.

I have since driven it short trips (about 5 miles) six more times, and the CE light still remains off.

What the heck do you think is going on?

DBear