chuang

Dear all, kinda new here. Thanks for reading this.

Last Friday I had one day off and our 2004 C230 "Service A" was past due for 500+ miles. As I didn't plan ahead and all local dealers service department were all booked up, so I drove 35+ miles to a dealer that is kinda far away for "Service A."

To make the long story short, the "service advisor" convinced me to do some extra maintenance works other than the flexible "Service A". The works that were done are:
Replace engine air filter (and housing cleaned up) => $97
Replace Gas Filter external style gas filter => $285
Replace Spark plugs => $195
Replace brake fluid => $165

I was charged for $8xx for everything and was promised to have everything done by 5pm. At around 2:30pm, the "service advisor" called me and told me that they found two other problems:
The 13-pin is leaking
The front thrust link bushings is bad (has some cracking)

For these two items, he quoted me with another $8xx, which I denied on the phone. After 5pm, on my way back home, suddenly the "check engine" light gets turned ON while I was driving on the highway. I called the advisor right away (it was already 5:30pm which they are almost all ready to go home). As the next day I had to work, so I can't bring the car back to the dealership right away.

The next evening, I took it to a good car mechanic friend of mine (he mainly repair toyota's). He used his AutoScanner Diagnostic Code Scanner and found the error code was:
P0171 - System too Lean (Bank 1)

He reseted the "Check Engine" light and said that it's probably a faulty sensor or somewhere has a minor leak, no big deal. However, the next day while my wife is driving, the "Check Engine" light was turned back ON.

Here are my questions:

1. Based on the maintenance work that was performed, is it possible that one of the tasks performed caused that "Check Engine" light to turn on? Before I took the car to the dealer, that light was OFF.

2. Could it be caused by the two items that I denied (the "13 pin" or the "front thrust link bushings cracks")? If so, why didn't the "Check Engine" light turned ON before I took the car to the dealer?

3. I'm struggling about whether I should take the car back to the dealer for further repair, as I have sort of lost my confidence with this particular dealer. If I take it back, it's a long drive plus there is no guarantee that they won't charge me with another big $$$ just to get this "Check Engine" light turned off. My mechanic friend said that he could probably fix it, but then if the dealer is responsible for this issue, I really hate to have my friend fixing it as I will have to pay him. Any thoughts or comments? Thanks again!

LILBENZ230

It is possible, but anything is. It is also possible that it is merely coincidence. I would recommend finding an independent mechanic that can do your work and not the one you mentioned in your post. The mechanic who blames a CEL on a faulty sensor or "leak somewhere" when the code is 0171 lean has zero credibility and isn't qualified to work on lawn mowers. The CEL will not come on in response to a suspension problem, either. It is monitoring the emissions system.

W203E35

Take it back to the dealer and see what they say. Tell them what you told us. It might be during repair that they accidentally unplugged a hose or something went wrong.

If they BS you tell them "Hey buddy I just spent a lot of money here atleast you can do a free diagnostics and tell me what the problem is". If nothing ask for a manager, also I know some dealer have free diagnostics so mention that to them as well.

Good Luck, hopefully it was a mistake on their end.

With all my bad experiences all I know is that these dealers are crooks. I took my car in 8 times (luckily it had warranty) and I myself found the problem which they finally fixed.

walterk55

I feel for you ... my experience is that Service Advisors must be paid on commission and so look to run up the bill. Isn't hard to ask the mechanic to give it a "good look over". Reminds me of the time my service advisor at a VW dealer told me I needed new disk pads. With less than 10k miles on the car, I was surprised and took the car to an indy who popped off the wheel and showed me that I had at least 90% of the disk pad thickness remaining.

FIND A GOOD MB INDY - you are off warranty - you should not be going to a dealer... jmho

mleskovar

Common problem that could lead to a transmission malfunction and expensive repair if not fixed. Karo's advice is right on.....

91RS

I would be willing to bet something is off on the airbox that is causing the lean code to set.

chuang

Thanks for everyone's help. I will take the car back tomorrow, and will report back the result. Thanks again!