New Owner experiencing something weird

Hello,
I finally took the plunge and bought a 2012 LR 4 with 50K miles.
Overall it's a great truck. My only complaint so far is the sound of the engine; it doesn't have anywhere near the "V8 grunt" sound as my Mercedes ML 500 truck but the engine feels strong.
So, among the first things I did was install a trailer hitch and wiring harness. Very straightforward and no complications.
Next, I replaced all brake pads (EBC greenstuff) and rotors (EBC). The original pads had about 50% left but one or more of the rotors must have been warped because the truck would slightly vibrate during hard braking (now it no longer does it).
So here's my dilemma: I could not reinstall the original brake pad wear sensors (already ordered new ones and will replace them soon) so I left them disconnected. The rear sensor was not secured properly and after a few days it got damaged and the "worn brake pads" message appeared on the instrument cluster. Being used to the simplicity of Mercedes vehicles, I assumed the wear sensor only had one wire which is normally open and makes a ground connection (closes the circuit) when the sensor is destroyed due to brake pad wear. Well, as I later found, it's the opposite with the LR 4 (normally closed circuit and opens when brake pads wear). So while I was figuring this out, the truck kept giving me the "worn pads" message so I disconnected the brake wear sensor from it's electrical connector and got all kinds of warning messages, such as ABS malfunction, etc. When I reconnected the wire and then soldered the brake wear sensor's wires together, all went back to normal and no further messages were displayed on the instrument cluster.
Could this have RESET the computer? I'm asking because I immediately took it to the dealer to perform a state emissions inspection and they told me they can't communicate with it yet; that it has to be driven for a couple of hundred miles. This is the typical symptom when either of two things happen:
1) A check engine light appears and is RESET (or any emissions related code) using a scanner/reader or
2) The battery is disconnected (clearing the emissions information).

Well, I did neither of those things but my guess is that tinkering with the brake pad wear sensor resulted in a computer RESET and don't understand why it would happen. I guess the software code in cars these days is so complicated that anything is possible...

Any comments? Ideas?

Thanks

Sergio

max2105 said:

So, among the first things I did was install a trailer hitch and wiring harness. Very straightforward and no complications.

Click to expand...

I can't help on the brake stuff but I am curious what trailer hitch you installed. I have a Curtis coming in on Friday with plans to install. I wasn't able to find another and the Curtis requires me to remove my full sized spare. Just wondering if there is another Class 3 option before I install this one.

Dan

Hi Dan,
I got a great deal on ebay. Both hitch and wiring harness for under $150.

Sergio

http://www.ebay.com/itm/Atlantic-Br...2b7FqafY%2Fk1N5uNo95g%3D&orig_cvip=true&rt=nc

I'm at wits end with this vehicle! Even after driving the truck for over 400 miles the LR dealership can't figure out why the vehicle won't allow it to perform an emissions test. They've had it for 4 or 5 days and have worked on it countless hours. Spent time talking to LR tech support and still can't figure it out. Now they're waiting for a LR engineer to show up. In over 15 years of owning several Mercedes vehicles, I've never experienced this before. This is a vehicle which had a pristine service record for almost 50K miles (different dealership) and since taking it to our local dealership it's been nothing but problems. On top of that the airbag light also came on. Couldn't pull any codes with my AUTEL OBDII reader but they claimed it was a defective seat belt buckle. They replaced it, reset the light and now it came back on. I suspect when they replaced the back-up camera wiring harness, something got disconnected/damaged.
I advised them to reflash the ECU or disconnect the battery. They said tech support recommended they RESET the entire vehicle and start from scratch but the vehicle won't allow them to RESET it!
Hope they can resolve this because we truly love the LR4 but if this is what's to come in the future, I'll get rid of it.
Has anyone had a remotely similar problem?
Thanks

Problem solved. It was a bad O2 sensor. I spoke with the service adviser and told him to have the mechanic look at the O2 sensor data (one of the short term parameters was all over the place when I hooked up my AUTEL scanner and monitored "live data.") but he kept insisting they had done that. He now told me they followed my advice and looked into it more and found the bad sensor. He said it's weird because "it wasn't triggering a check engine light" (they don't always do that anyway). Lesson learned; if you want something done right do it yourself.
The airbag light was due to a loose connector they did not plug in properly.....
Hope this can help someone else in the future...

Sergio

Glad we could help!

Thanks for the follow up.

For those of you looking for a better hitch solution, drop me a line w/your e-mail, I can send you some info. That way you can keep your spare, and have a better option.

All that hassle and a bad 02 sensor disables computer, that's really strange.... but good info to know if it comes up for someone else..

Crazy to think that after something gets repaired if the electrical parts aren't put back exactly as they were you can get some wild symptoms. How frustrating when it's only a connection problem.


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max2105 said:

My only complaint so far is the sound of the engine; it doesn't have anywhere near the "V8 grunt" sound as my Mercedes ML 500 truck but the engine feels strong.

Sergio

Click to expand...

This sounds like you need an aftermarket exhaust. Magnaflow makes one and others may also. For the LR3 Magnaflow actually has down pipes or headers too which I am quite curious to hear.

I have a Borla on my 2004 Disco and it's pretty sweet.

Well, when the engine is first turned ON and it idles, it makes an awkward "rattling" sound, as if something was wrong with it. A few seconds later (oil pressure builds up?) the sound improves and it sounds like a "normal" engine. I test drove another LR4 that did the same exact thing. We got a Jaguar XF loaner vehicle while the LR4 was at the dealer and its engine also made the same noise. It just doesn't sound right....