Hi All,
I have been a long-time reader but this is my first post. I have a 2006 LR3 V8 w/ 170k miles and love it dearly.

Last week while driving something happened suddenly that caused a complete loss of engine power, limited RPM's, and a very colorful dash. The engine didn't stall but it ran very rough and would barely rev or go more than a few MPH. I was able to limp it a couple miles home and went so far as to reverse it up a hill in my neighborhood because it didn't have enough torque to go forward. I figured the lower gearing of driving in reverse might help and I was able to actually get it home. In hindsight 4 low would have been a much better solution but it never even occurred to me (would have been way too easy and not as flashy as going backwards in a LR up a busy road in the middle of the day).

Some context:
A few weeks ago it was slipping out of drive and eventually I could only shift it into drive but no other gear. It felt like a cable issue so I brought it to my trusted mechanic to check it out and change the oil. I wasn't needing the car so it ended up sitting there for a while but when I eventually went to pick it up he had decided to punt on the transmission and mumbled something about the Land Rover shifting being a complex computer algorithm that only the dealer could solve. Then just before he hit me with the $150 bill for the oil change he did go through the trouble of crawling underneath the vehicle with me to show me how to shift the gears by pulling the little lever on the transmission - the same one that had a loose cable on it.
Once I got it home I took a wild guess to check under the center console and found that the cable (both inner and outer) had popped out of the stationary mount. Nothing was holding the outer cover of the cable in place so that just the inner portion would move (think bicycle hand brake). While I was working on that I noticed that the driver's side floor was pretty wet. The car had been at the mechanic for a few weeks and was outside in his lot so my guess was it was the sunroof issue. I'm not sure if the transmission issue is connected to this current problem so I am mentioning it just in case.

Once the shifter was fixed the LR ran great and we opted to take it on a short road trip get-away. She ran like an ace and got us there and back with no mechanical issues at all. However, along our drive we hit a few patches of very heavy rain and at one point water was actually leaking through the sunroof area on the driver side. That had never happened before but I knew of the sunroof problem and how to the fix it so I planned on addressing it as soon as we got back.

Now to the saga...
When I lost power a couple days after our trip the immediate symptoms were the suspension dropping and several faults hitting the dash: transmission (in "F"), suspension, HDC, engine, parking brake, system unavail, etc. I shut the engine down and restarted it but everything stayed on and it continued running very rough with a max rev of around 1800 rpm's. Once I got it home I hooked up my diagnostic scanner - a mediocre Innova 5023, and that pulled several codes that are listed below. Once I got under the hood I found a set of wires that were plugged into a harness on one end but severed on the other. After pulling some of the plastic off I figured it out to be the (5) wire harness for the fan clutch. My guess is that the fan caught it and ripped the plug out leaving the bare wires at the end. The end that plugs into the fan is gone and finding a replacement is impossible unless you buy a new fan clutch (a rant for another time).

Codes that I pulled:
P0102 (MAF low input)
U2023 (scanner did not define but I have found it to be transmission ECU)
P0480 (Fan 1 Control Circuit)
P2103 (Throttle Actuator)
P2105 ("Throttle Actuator Control System - Forced Engine Shutdown")
P0121 (Throttle/Pedal Position Sensor A Circuit Range/Performance)
P0113 (Intake Air Temp Sensor 1 Circuit High)
P0607 (Control Module Performance)

After taking to google and the abundant LR forums, I have gone ahead and tried the following thus far:
Purchased a decent multimeter to check battery voltage. Battery voltage within the numbers advised.
Removed and cleaned MAF.
Replaced brake switch.
Hard reset (several times).
Made a rudimentary plug hack for the fan clutch to verify that it still works and has power - it does.
Ripped most of the car apart - removed cowl, exterior a-frames, sills, etc. looking for water damage or corrosion. So far I found one pin in one connector that looked a little off. Have been spraying everything with electric spray.
Disconnected all ECU plugs, removed and inspected the TCU - all dry.
Verified power going to throttle sensor and MAF sensor with my new voltage tester.

When I do the hard reset or try to clear the codes the faults hit the dash as soon as I turn the key to the on position. And right behind it is the Innova pulling those same codes. It always turns over and actually starts but it doesn't always stay running. I would say for every 4 times I start it, 3 times it will shut right off after it fires.

I am trying to rule things out as I can but hope is fading. My hypothesis is beginning to lean away from water damage and more towards the loose wires from the fan-slaughter causing a short that fried the ECU or something along those lines. Nothing that I have done so far has had any effect whatsoever.

As I was about to pull out the ECU tonight to inspect it for water damage something told me to pause and write this instead. I adore the vehicle and really do not want to do anything else that might potentially cause more harm than good. I am hoping someone with more knowledge can share their thoughts. If I continue on the path of ruling things out (more interior digging and changing out sensors - O2, etc..) I might be heading towards a financial imbalance that I can't justify but I also don't want to give up just yet.

Thanks!

 

Welcome to the forum. It sounds like you are working on a problem more associated with water ingress. A common area is like you indicated, the sun roof. Trouble is this can go down the inside fuse box causing all sorts of problems. Another area that gives problems from leaks are it gets into the sills and there are many joins that can cause problems. Most of your problems will possibly be bad connections.

 

Usual suspects:

1. Water ingress from windshield cowl (check cabin filter, if wet then it's leaking), sunroof drains (wet floorboards, access to both in cabin) or A/C drains (wet floorboards, access is just under the sides of the center console)

2. Brake position switch, cheap fix and is right above the pedal

3. Power issues. Dying battery, corroded battery terminals, dying alternator, corroded ground strap at body connection