Need some help with my parents' 2004 Chrysler Sebring sedan. It's the Platinum Series V6 with around 75k miles.

I noticed when walking up to it about a week ago when the engine was on, that it sounded extremely loud. I don't know if it's the engine or exhaust. It's been doing this for 2-3 weeks according to my mom, and then a few days ago the CEL came on. They haven't brought it to Autzone or anywhere to pull the code, so I don't know if I have enough info for you guys to guess what the problem could be. Also according to my mom, it's not driving any differently. I only rode in it once since this problem started, and have not driven it so I can't say if anything is really out of the ordinary.

Car is going in for service on Thursday but just wanted to try to get an idea of what to expect.

 

Did you check the oil? I'm serious.

 

It could be a million things, getting it checked will narrow it down to a few dozen.

 

That's what I figured.

And no, I didn't check the oil, maybe my dad did. I haven't seen any leaks, but I guess it could have been burning oil.

 

*shrug* FYI - Some of the 2.7 L V6 engines have suffered from failures due to oil sludge contamination. These problems happen when fine engine oil passages become clogged with sludge, and often result in catastrophic failure of the engine. Improper maintainace, such as irregular oil changes would see such results. An unknown number of Sebring, Concorde, Dodge Intrepid and Stratus owners have been affected. Fixes include changing to synthetic oil, inspection, and even engine replacement.

 

I'm pretty good at diagnosing things, but would need a touch more info to offer anything helpful

 

Hmm, I know they have done regular maintenance on it, so hopefully it's not a sludge problem.

I'm curious to find out the problem, though. Just happened out of nowhere. The only thing that bugs me is that my parents drove the car around for one or two weeks with this going on, before the CEL came on. Whatever it is could have been made worse by not making an appointment earlier.

 

Yeah, it would help if I had the code.

 

Update, car is back from the shop. Findings:

Code: P0137 (Oxygen sensor low volts)
Note: Has an exhaust leak. Needs a resonator exhaust pipe.

Mom said they told her they need to do further tests. So what's going on?

 

Hi LMTSX

Nothing to really worry about. I'm sure you know a car's ECU is responsible for an engine's operation and emissions. The O2 sensor is an integral part of this system. An O2 sensor does exactly what it says it does, it senses the amount of oxygen in the exhaust of an automobile. The O2's electrical output is directly tied the amount of oxygen it senses.

If the sensor reads a little too much oxygen in the exhaust, it lowers it's voltage output. It's basically sensing a lean condition. Alternatively, if it senses a rich condition it sends a higher voltage. This voltage is sent to the ECU which adjusts the fuel/air mixture. What your parent's car is doing is the O2 sensor is indeed sensing a lean condition, lowering it's voltage, and sending the information to the ECU. The ECU is confused as it cannot properly make the correct adjustments, and activating the CEL.

Why is this happening? The exhaust leak. Modern cars do indeed need sufficient back pressure to operate. Depending on the location of the leak in the exhaust, air is actually being pulled into the system. The O2 in turn incorrectly reads this as a lean condition, lowers its voltage, and tattles to the ECU, which cannot fix the problem correctly.

Repair the exhaust and all will be fine.


Terry

 

Terry hit the nail on the head.

On a side note, congrats on the promotion Terry! I imagine Goat and Kona were pleased.

 

Thanks Terry! After thinking about it, I figured it was running lean because of the leak. I learn everything I know about cars on here from all of you guys, so thanks!