Where do these wires go?

evobilly666 · Mar 21, 2023

L320 TDV6 2008

Have just replaced hpfp belt. Disconnected all the harnesses at the tccm and pcm to make access easier. Have put it all back together and lost communication with the tcm.

All contacts for the three plugs on the tccm are clean and corrosion free. I have also cleaned them with contact cleaner and applied dielectric grease.

There is one small plug with a red wire and a red/green wire that I cannot find anywhere to plug it in, neither do I recall unplugging it although its possible I did. Does anyone know where it would go? it is only short but i cannot find anywhere it would go.

Datatek · Mar 21, 2023

evobilly666 said:
L320 TDV6 2008

Have just replaced hpfp belt. Disconnected all the harnesses at the tccm and pcm to make access easier. Have put it all back together and lost communication with the tcm.

All contacts for the three plugs on the tccm are clean and corrosion free. I have also cleaned them with contact cleaner and applied dielectric grease.

There is one small plug with a red wire and a red/green wire that I cannot find anywhere to plug it in, neither do I recall unplugging it although its possible I did. Does anyone know where it would go? it is only short but i cannot find anywhere it would go.

dielectric grease.? That's an insulator is it not?

evobilly666 · Mar 21, 2023

I'm not sure, it was recommended by automotive store. Either way, I have no communication with TCM when I had cleaned the contacts prior to trying the grease. Car was fine prior to stripping it for rear belt so it is something that I have disturbed.

Datatek · Mar 21, 2023

evobilly666 said:
I'm not sure, it was recommended by automotive store. Either way, I have no communication with TCM when I had cleaned the contacts prior to trying the grease. Car was fine prior to stripping it for rear belt so it is something that I have disturbed.

Personally I would start by cleaning the grease off.

evobilly666 · Mar 21, 2023

I can do that, although the fault existed prior to application of the grease

gstuart · Mar 21, 2023

Plus 1 ^^^^^

That small plug might be a transport connector , does it sit next to the battery and the other large grey connector plse

plse also check the fuses are ok to ensure after using the grease u haven’t shorted something out, along with ensuring the wires are secure inside the connector and that they don’t push back when reinstalling the connectors

can u communicate with all the other modules or is it just the TCM that u can’t plse

hope that also helps

evobilly666 · Mar 21, 2023

Hi, I have checked the three fuses behind the glove box and the one 8n the engine bay. All have continuity and light a test lamp on both legs. The transmission control module is the only one I cannot communicate with. The pcm, tccm, abs module, dsc, sls and a few other modules all throw a code as 5hey cannot communicate with the transmission control module. Will clean the grease out tomorrow although I feel its a red herring as silicone grease is designed to prevent short circuits as a result of corrosion so can't see that being an issue.

gstuart · Mar 21, 2023

evobilly666 said:
Hi, I have checked the three fuses behind the glove box and the one 8n the engine bay. All have continuity and light a test lamp on both legs. The transmission control module is the only one I cannot communicate with. The pcm, tccm, abs module, dsc, sls and a few other modules all throw a code as 5hey cannot communicate with the transmission control module. Will clean the grease out tomorrow although I feel it’sa red herring as silicone grease is designed to prevent short circuits as a result of corrosion so can't see that being an issue.

Must confess I’ve always understood dielectric grease to be non conductive and a moisture repellent, it will not allow you to make an electrical connection between two components, of course stand to be corrected

have in the past had a lot of electrical issues at the TCM and ECM searching for the issues so can sympathise

u can also carry out canbus tests, also is the battery fully charged and what codes have u been getting

hope that helps

Datatek · Mar 22, 2023

gstuart said:
Must confess I’ve always understood dielectric grease to be non conductive and a moisture repellent, it will not allow you to make an electrical connection between two components, of course stand to be corrected

have in the past had a lot of electrical issues at the TCM and ECM searching for the issues so can sympathise

u can also carry out canbus tests, also is the battery fully charged and what codes have u been getting

hope that helps

View attachment 284825

As above^^^^^ the grease is likely to create bad connections.

gstuart · Mar 22, 2023

Datatek said:
As above^^^^^ the grease is likely to create bad connections.

many thks as indeed wasn’t 100% sure with regards to that grease

As a side note when I had issues I got some terminal files that allowed me to very carefully remove the green build up on the TCM , took me a good hour as didn’t wish to be too aggressive on the terminals , then used some electrical cleaner on the TCM & ECM plus connectors , plugged my diagnostics in, reset everything , no codes came back which was a right result , took me ages trying to line up the module cover, in the end used some small cable ties which snugged up the cover nicely , mainly to prevent any water ingress

did also find and thoroughly clean the earth posts that went to the modules

Thks again

Datatek · Mar 22, 2023

gstuart said:
many thks as indeed wasn’t 100% sure with regards to that grease

As a side note when I had issues I got some terminal files that allowed me to very carefully remove the green build up on the TCM , took me a good hour as didn’t wish to be too aggressive on the terminals , then used some electrical cleaner on the TCM & ECM plus connectors , plugged my diagnostics in, reset everything , no codes came back which was a right result , took me ages trying to line up the module cover, in the end used some small cable ties which snugged up the cover nicely , mainly to prevent any water ingress

did also find and thoroughly clean the earth posts that went to the modules

Thks again
Wow, that was one badly corroded connector! Don't forget to remove any verdigris from the plastic between the pins as it will affect the signals.

View attachment 284849 View attachment 284848 View attachment 284846 View attachment 284847

gstuart · Mar 22, 2023

Many thks as always

Funny u saying that as I was meticulous in ensuring both the terminals and connector were nice and clean , not too clean so to speak as I read somewhere they have like a thin coating on the terminals , seemed to take me forever as just took my time to ensure everything was nice and clean without overdoing it

plus meant to say as I imagine u would find this interesting , , got a break out box a few months back , didn’t realise u can have an ECU out of the vehicle for testing , alas though wouldn’t attempt it in case I accidentally done something wrong

mystery · Mar 22, 2023

Land Rover do recommend in some of it's workshop manuals BAU 5811 grease for connectors if removed which is equivalent Electrolube SGB20S
https://support.newgatesimms.com/how-electrical-connector-lubricants-work/

Datatek · Mar 23, 2023

mystery said:
Land Rover do recommend in some of it's workshop manuals BAU 5811 grease for connectors if removed which is equivalent Electrolube SGB20S
https://support.newgatesimms.com/how-electrical-connector-lubricants-work/

I would have to dispute points 1 and 3, this company obviously want to promote their product.

mystery · Mar 23, 2023

Datatek · Mar 23, 2023

mystery said:
View attachment 284893 View attachment 284894 View attachment 284895

No trace of grease in the connectors of any of my cars, nor was grease used in the multitude of connectors used in computers.
Grease will always pick up dirt.
Maybe it was used in some JLR products because the connectors are such poor quality.

mystery · Mar 23, 2023

It's not JLR it's the Italian, Japanese, Chinese and German looms ,connectors , control modules and cabling suppliers.
most computers for many years have use gold plating contacts but then they are not subjected to water ingress until they end up on the scrap heap so no grease
whilst the Automotive suppliers have tried plated copper, brass and even steel contacts (Ford being one of the first to try plated steel )

Nodge68 · Mar 23, 2023

Datatek said:
dielectric grease.? That's an insulator is it not?

Indeed it can be, although it does depend on the type of connector as to the extent of issue it'll cause. A secure bolted connection will be fine, but a fine spring connection like in ECM multi-plugs, yes it'll do more harm than good.

I use it all the time, but only on the sealing gasket, not the electrical connections themselves.

kermit_rr · Mar 23, 2023

Datatek said:
dielectric grease.? That's an insulator is it not?

Non conductive, can help stop tracking etc while keeping moisture out but not impact a good connection

kermit_rr · Mar 23, 2023

Personally, i use dielectric on HT leads, stops the leads sticking to the plug etc

Where do these wires go?

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