Te mechanic says there is no power from the ECU but all the other modules work good, and the grounds seem ok.

 

Hi. I'm new to the site but you may want to try resetting the fuel reset under the hood.

 

I believe that has been done.

The huge problem is that there is no power from the ECU, and the ECU looks spotless inside and out. The shop is completely convinced it's the ECU, I am not too sure.

I am in a rough spot here because the truck in now torn apart in the shop, I have an ECU on my desk, and a brand new exhaust system in my living room, and my truck won't start and is just flashing.

My front sunroof stopped working a while ago, and I really want to love my moneypit truck since I have probably replaced everything in it by now, but I just need to get this figured out.

The mechanic says it's simple. No power from the ECU, so the ECU is dead. the M & S lights and the flashing D, I have no idea what to do anymore. They seem to have tested everything, so I just don't know what else to add.

 

Did they check the power and grounds going INTO the ECU?
A bad or broken ground wire can cause all sorts of trouble and often the ECU won't communicate with a scan tool.
One good (and simple) test you can do is, disconnect an easy to get to sensor like the throttle position sensor and test the wires. One of them should have 5volts. If not, the 5v reference is either shorted or the computer doesn't have a good power or ground. I wouldn't just replace the ECU without a lot of testing. I see it happen all the time, someone changes the ECU only to have the same exact problems as before.
Sometimes a sensor on the 5v reference shorts internally and it will pull the whole 5v circuit to ground, so none of the sensors will work.

 

Have you tried resetting the ECU by disconnecting the battery and connecting the terminals together with a piece of copper wire to completely drain the ECU of power? Chances are if that didn't work you need to look for exposed wires or corrosion near the ECU and the wire harness that's draining volts from the ECU. That's why you have the flashing M&S and D on your display.

 

They have said they have tested all the grounds, and I have the ECU out of the truck and sitting on my desk here.

The truck was running fine when I drove it to the shop to have them look at the muffler and when they turned it on again, all the lights came on and it wouldn't start.

I actually went in myself and tested fuses and grounds and didn't really see an issue, and the mechanic is very good with electronics and was showing me the whole wiring schematics for the truck.

I just don't know how the ECU would just die, but they have spent days trying to trace an issue.

 

You said the sun roof stopped working? The motor might have got water damage which could have spread to the security switch thats up there as well. I mean it could be as little as some corroded soldier.

 

I have two sunroofs and only the back one is working, however that happened quite a while before this.

I am not sure if it would cause no power to/from the ecu.

 

I am still looking to resolve this issue as soon as I can, but have ordered a used ECU just in case, at least we can see. what happens. At east if the truck starts we are getting somewhere.

I am not sure if the M & S lights have anything to do with the ECU, but since there is no power we will have to see, unless anyone has more suggestions.

The security system seems fine and the truck can arm and disarm without issues.

 

You can't just swap in a used ECU, it has to be synced using Land Rover specific tool.

Or, you need to change the ECU, BECM, and gauge cluster as a set.