Merry Christmas,

I'm looking for a little help as I'm stumped as well as the dealership. I seem to be getting error codes that trip the engine light. When I take my vehicle in the code appears yet no problem are found. And once the engine light is reset it does not appear again for 2 weeks to 2 months.
The error codes that I have been receiving are as follows and I will provided the circumstances in which the engine light comes on.

The first fault code is PO171- B2S2 bank 2 running lean. This code appears between 5 to 10 minutes after start-up and when the engine is idling typically in stop-and-go-traffic.

The next code that appears infrequently is PO420 - cat efficiency. There are no driving circumstances in which this once appears.

The newest code that appeared, but I cannot remember the number but the information is B2S1 malfunctions/low voltage. This code has appeared twice in the last two weeks under almost identical circumstance. The first instance the engine light appeared was 20 minutes after start-up highway driving. My cruise-control as set at 120km/k (70mph) and I has to cancel the cruise-control as I got cut off. The second time, yesterday, and I'm assuming its the same code- I was on the highway cruise-control set at 130km/h(80mph) and the engine light appeared. Since dealerships are closed I cannot get the error code.

Every time I go to the dealer I get the fault codes yet all of the sensors are within operating specifications, my cat is in fine working order, and the problem is still present. It appears that all the codes are related to bank 2 side of the system. I was just wondering if anyone else has experienced this problem and if so the solution that has been effective.

Or is there a "gremlin" in my system that is causing these anomalies to appear and set off the engine light.

Any help would be greatly appreciated as my fear is that the "never cry wolf' engine light comes on and I ignore it and there will be a serious problem that I will ignore due to what I'm currently experiencing.

On a plus side with all of the codes being read at the dealer, my transmission shift problem has disappeared

 

WOW, what a terrible technician you had,

replace the affected oxygen sensors.

it is possible that they can be in spec (ie at the shop) and then go out of spec (your examples). thus the tech thinks they are ok (prob. an apprentice)

the trouble codes for oxygen sensors can and will set a code for cat effiency. so i would leave that code alone til you get the oxygen sensors installed and see if they make a difference.

most people dont know this but, oxygen sensors only have a typical life of 100,000 km ( 60,000 miles). they work in pretty demanding situation. you may even notice better fuel economy with them replace as they will read correctly and more accurately.

expect to pay about 150 per sensor, and .5 to 1.0 hours of labour to install (this is dealership pricing) there are many places online that sell good quality parts for much less.

 

This could be covered under your emissions warranty depending on your state. Check your owners manual. The dealer will usually charge you until you point out that it's covered.

 

Start with B2S1 that will cause the lean condition, and there is a TSB EG022-05 for this problem, that recommends the upstream (b2s1) sensor be replaced.
Its only warranted to 4years/50k.

Reference the TSB to the dealer. Sorry they missed it. We are not all the same.

 

http://www.epa.gov/oms/consumer/warr95fs.txt

Check it out. It could be up to 8 years or 80,000 miles. The owners manual will spell out which parts.

 

Hello everyone,
Thanks for the great information. My vehicle is off to the dealer on January 4th for the brake recall. I think they will have other stuff to do as well.
Chris

 

Good luck with the CEL's. They will take care of you.