[JohnnyD]

Recently my Check Engine light came on with a O2 sensor lean signal, meanwhile my "Time for Service" display keeps showing up. I can clear the "Time for service" and in a few starts it's back. I replaced the O2 sensor yesterday and had the code cleared and today it's back. I went to the dealership to have the code read and it was O2 sensor lean signal again. The dealer said it's probably the D.I. Cassette (red).

Could this be true or are they just trying to steal my hard earned cash?

 

[20Ted]

Check for a vacuum leak in the system somewhere first - they can cause O2 sensor faults. Also, if they didn't brighten the metal in the downpipe where the O2 sensor goes and there is any rust present, then the O2 sensor isn't grounded very well - that can cause the fault code as well.

If you do want to replace the DI cassette to see if it corrects the problem - do yourself a $300 favor and go to a junkyard somewhere and buy a used one for approx. $50 - $100, especially since you have an iffy diagnosis from the dealer (iffy at best!).

PS - the 'Time for Service' message in the SID has NOTHING to do with something being wrong with the car. It's a reminder message that cycles through based on the number of starts the car has (averaged out for approx. 10,000 miles IIRC)