My 2005 LR3 with 170,000 miles recently started having a throttle position sensor issue that caused the land rover to go into limp mode with an engine fault warning. I found a loose connector that goes to the mass air flow sensor and plugged it back in. I then tried to clear the codes on the LR3 using my OBD II scanner that I’ve used multiple times before. Now after trying to restart the LR3 I’m getting no signs of life at all. There’s a “click” when I turn the key over but the starter doesn’t even attempt to turn over the engine. The battery was charged and tested to verify good cranking amps and voltage. When I attempt to read the codes my code reader now says “ECM Not Equipped” and it reads no codes as a result.

Is the LR3 dead in the water? I’ve tried to research if there are any fuses or relays that control the ECM specifically that might be burnt out, but I haven’t been able to find much info on this. I’ve read that a ECM/ECU replacement is costly and in my situation would most likely mean scrapping the vehicle for parts. I tried removing the battery and leaving the vehicle overnight to see if it would somehow clear and reset. But no luck. It continues to show no signs of life. Any recommendations??

 

I would say there are multiple areas to probe.

Starter...ECM....battery ground cable...and your code reader itself. The generic ones are not as useful with the LR3.

Of these things, I'd probably start with the ground cable. Then starter, then code reader and finally ECM.

 

Thanks for the suggestions. I'm using a LAUNCH CRP Touch Pro scanner. It's always worked decently well across a wide range of vehicles that I've owned, but it scares me most recently with not even detecting the LR3 ECM. I'll put some time into verifying the grounds are all solid and firm and I'll give the starter a few good knocks to see if anything can be broken loose within that might be binding it. What code reader would you recommend? Factory IDS-VCM? I don't have a Land Rover dealership/repair shop within a couple hours distance, so I'm trying to avoid hauling it all that way if I can help it.

 

IIDTool by GAP Diagnostics.

 

Have you inspected the EMC and connections? It's behind the battery.

Is your cowl plastic warped? Any recent water/leaks?

 

I did pull out the battery to look at the connectors behind it. I thought that the ECM was somewhere located in that area. I couldn't see any connectors that looked corroded, broken, or out of place. I'm going to try discharging the battery by connecting the negative and positive cables for a few minutes and then try to disconnect and reconnect any and all plugs/connections behind the battery just to make sure. Do you know of any specific fuses or relays that might be involved?
The cowl looks good. No warping. Things appear to be as they should be under the hood.
I should have mentioned earlier that the thermostat housing had recently started to leak (back in the summer) as the plastic part had started to degrade from the excessive heat exposure through the years. That's why I parked the LR3 for a couple of months. I recently had the thermostat housing replaced To replace the thermostat housing you have to take off the MAF and I'm sure that's why the connector was loose. Right after the thermostat housing was replaced the LR3 would start but was in limp mode with an engine fault b/c the MAF sensor wasn't receiving data as the connector was loose. And then when I plugged back in the MAF sensor securely and reset the codes, the LR3 is now seemingly dead and the code reader no longer recognizes the ECM at all.

 

I'm not quite sure yet how an unplugged MAF sensor will lead to a dead LR3 after re-plugging.
Issues might be unrelated, just coincidental?

A quick scan of the manual shows you might try:
Engine: F5, F6, F10, F11, F13, F17, F27, R6, R13, R18
Interior: F25, F28, F60

There may be others I didn't list.
If you have a fuse tester, you can run down and get any/all fuses quickly.