Help!
I cant now get my new Nanocom to communicate with the engine ECM.
I have trawled through the previous posts but none seems to be the same as my problem.
I have done the normal things: check continuity and cleaned earth / ground points.
Here is the back ground, sorry its so long.

I purchased brand new Nanocam through Empire Tuning 3 or 4 weeks ago.

The car had an engine misfire so I purchased the new Nanocom to help me. (They expensive and this fault sort of justified paying for one).

My vehicle is 1999 P38 Gems with 4.0 V8 petrol. Manual gearbox.
The air suspension was removed before i bought the car 3 years ago.

Initially the Nanocom intermittently connected to the engine ECM and the BeCM. (but not the ABS).

The Nanocam reported "code 1364 no ignition coil activation coil 4 cylinders 2-3".
Also code 0113. Air intake temp circuit high. minus 61 deg C.

Trial and error and new plug leads and a new coil pack confirmed it was actually coil 3 that was the problem (spark plugs 4 & 7) and that was due to a poor connection in C525 on the white / yellow return wire from coil 3 back to the ECM conn C509 / Z132. ("pin 15").

So the misfire is fixed and the engine runs fine on all 8 cylinders.

I have bought a second hand air temp sensor but after a clean of the temp sensor bulb in the air filter box the temp read ok, so i've not fitted that yet.

Having fixed the misfire which made me very happy i then realised i could no longer get to the Nanocam to comm with the engine ECM, and only very intermittently with the BeCM etc. (Still no comm with the ABS). Message is "error, unable to start communications with the ECU".

Therefore i set about cleaning connections and earth / ground points and checking continuity from the OBD port to the various "computers".

I had previously (3 years ago) soldered in a new / secondhand OBD port in passenger LHS footwell and worked from there. ( I did this as Les Edwards in North Wales did some diagnostics for me and suggested a new OBD was needed. When i returned to him having fitted the second hand OBD port and a new throttle position sensor the connection was ok)

Checks over the past 3 days confirm I have perfect continuity from the OBD port to the BeCM on the 2 diagnostic wires. C231 numbers 7 (pink / red diagnostic line K ) and 15 (Light green / red diagnostic line L ) to BeCM C255 number 8 and 17 same colours respectively).

I also have perfect ohms free continuity from the OBD port to the Engine ECM with the pink / red diagnostic line K wire. Interestingly the line L does not go to the engine ECM. The Land Rover wiring diagrams show it terminating at the Connector C106 at the ECM but it does not run from C102 to the Engine ECM. Land Rover manual and wiring diagram says "not used".

At the Engine ECM i have good earths or grounds.

The OBD port has 2 grounds. A black wire and a black / purple wire. (pins 4 and 5). The grounds are interesting and may be the problem. With battery isolated and "all off" i get zero ohm continuity from the OBD port to the vehicle's metalwork. But with the key in they do show some resistance, 0.5 ohms, and with the key in position 2 i seem to get even higher ohms. Also with the key turned position 2 i see a small current on my multi meter. Just a few milli volts. How is this leaking into the ground system? Possibly electro magnetic field from the unscreened wires running together?

So i am now stuck and need help.

I have done some good however with my clean up of the connectors and the ground points; i can now connect to the BeCM, and the HVAC and the airbags reliably every time with the key in position 1.

What do you think about the grounds? Could they be preventing the Nanocom from connecting to the engine ECM? I could cut the existing black and black / purple grounds from the harness near the OBD port and make a new OBD to body ground point locally. I presume a ground with "interference" may affect the Nanocom connecting?

How about the Engine ECM itself? Do they fail internally and "stop talking" to the diagnostic systems? Seems a coincidence for this to happen.

With the Nanocom i presume it is OK as if its communicating withe BeCM and HVAC and airbags then it should conn to the other items as well.

I have connected the Nanocom to my home PC and see i still have the unlock codes showing at "unlock 06" and "unlock 08".

I have not fitted the SD card, is that needed?

I have thrown a temporary direct wire from the OBD connector (pin7) to the engine ECM to run parallel to the pink/red diagnostic line K, but still no connection to Nanocom.

Trial and error showed me BeCM required key in at position 1 but Engine ECM required key position 2 and / or engine running.

Help please, any further ideas to get this Nanocom talking to my Engine again (and ABS).

Steve Bedder.

Ignore key position 1, all that does is turn on the accessory supply so nothing important at all. To connect to the BeCM the ignition needs to be OFF, to connect to all the other systems it needs to be in position 2 or, ideally, with the engine running.

A lot of the data to the OBD port goes via the 18 way white connector behind the RH kick panel which is notorious for corrosion (water leaks through the pollen filter housing drips directly onto it). Cut it out and solder the wires through directly, noting that one (or maybe two) on the pins have two wires into one pin.

ABS is a strange one. If you want to go into the ABS, do it first before going into any other system and after you have finished, reboot the Nanocom before trying to go into any other system.

You don't need an SD card unless you want to save outputs from systems.

One other little quirk I've found with mine is connecting to the HEVAC. On a first attempt, I always go into Settings first. Often it then comes up and tell me it can't connect, go right out and back in, go to Settings and it connects. After that it works on all menu items. One of my cars has an unlocked BeCM while the other is locked and it does exactly the same on other cars too.

Thank you for the rely.

Its super to get guidance and suggestions ...you can feel very "alone" when up against issues like this
(especially having spent now 3 full days investigating and apparently getting no where).

I have already checked and cleaned the white C102 / C202 18 way connector in driver's footwell (RHS).

My multimeter says there is continuity across all pins, but i have seen in other threads that owners have had success by cutting it out and soldering the wires together.

I will get my head in there this afternoon and at least eliminate that connector 100%.

Any thoughts on the two grounds into the OBD C231 connector? While the soldering iron is out i'm tempted to cut them both off and make a new ground to the M10 bolt adjacent which gives good earth. (Dash board support bracket i think). If I've got a slight current back-feed (or / and mystery resistance) up a harness ground wire then this should give the Nanocom a cleaner earth. What do you think? If it doesn't solve it i can put the grounds back as original.

Thank you for your help, any other suggestions welcome.

Steve Bedder.
Mid Wales UK.

Those connectors often have corrosion on the copper wires where they go inside the contact crimps. No amount of cleaning will fix it & you cannot see the corrosion without de-pinning the contacts from the housing.

Unless you plan to take the body off one day, the best answer is to cut, solder & heat shrink each wire (making sure the colours match each side).

Thank you both for guidance...any more ideas gratefully received.

I was concerned the two grounds to the OBD connector (black and Black/purple) had a resistance and a few miliamps when power was on to the vehicle metal work. This was without Nanocom connected. Maybe a insulation failure in the wiring loom?
I figured this may be inhibiting comms with the ECM so i have made two new local grounds close to the OBD connector and with my multimeter they have no resistance or millivolts showing now. (When the Nanocom is connected and operating a small resistance and slight current is detected but i guess thats the Nanocom working?).

However i still cant communicate with the engine ECM.

This is a bit of a puzzle as out of the box a few weeks ago the Nanocom gave me good information on the Engine ECM, but now its been lost some how.

Any chance i need to reload firmware?

I will now set about removing C202 / C102 and solder the 18 connections together (in the RHS footwell).

I've tested for continuity across this connector but i see from what you have said that I may just be proving the pins are connecting rather than the copper wire inside the pins.

I will let you know progress.

Many thanks for your guidance,

Please keep sending ideas.

Steve

The connection to GEMS also goes via C106 underneath the coolant header tank.

Thank you, yes i have checked and cleaned C106/C506 under header tank.

Do you know why diagnostic line L (light green red) does not go to the engine ECM? Presumably it only need Like K, the pink and red.

Yesterday i worked in the  right hand footwell, driver seat in UK, and removed the white C102/C202 connector and soldered all together. (18 connections but actually only 11 on my car).
Unfortunately i didn't get any improvement.
i already had 0 ohms continuity across the connector and indeed from the OBD port to the ECM on pink diagnostic line K to the Engine ECM, and to the BeCM.
Also 0 ohm continuity in the light green diagnostic line L from OBD to the BeCM.

So the Nanocam is still OK with BeCM and HVAC but not engine ECM.

Any other ideas?

I've isolated the battery for 10 minutes (many times) and then restarted everything. No different.

The alarm sounder has not worked for 3 years, it used to make me jump out of my skin when i isolated the battery outside that 15 second window. Its still connected though. Should i disconnect it?

Looking at the OBD port C231 pins, for the Engine ECM there appear to only be 4 which relate to engine ECM:

pin 15 light green red; line K main diagnostic, bi directional 0 to 12v.
pin 16 brown permanent 12v for diagnostic with 5 amp fuse at fuse 33 in fuse box.
Pin 4 black which is a ground or earth
Pin 5 black purple which is another ground.

i have concern about resistance building up in the black earth in the loom between OBD connector and the chassis as ignition key is turned
0.2 ohm with battery on
8.1 ohm and 2.1mv with key first click
17ohm and 4.7 mv key 2nd click ignition on,
19ohm 5mv engine running.

This is without the Nanocam connected.

I experimented with a local ground outside the loom from a local 10mm body bolt direct to the OBD grounds and get no resistance or millivolts in any key position.  However even with this clean ground to pins 4 and 5 the Nanocom would not still communicate with the engine ECM.  
So i reconnected to the loom grounds.

All very frustrating.

So i have an idea for another experiment.
Could i make up a OBD port ( i have a spare) and fit pins for the above 4 engine ECM related connections.
In the engine bay i could :
pick up a 12v supply (with 5 amp inline fuse)
make 2 perfect grounds (direct to battery?
And run a pink diagnostic line K directly to pin 23 of Connector 507 which goes to the engine ECM.
I have carefully pulled out this diagnostic pin previously from C507 at the ECM to check not corroded etc.
I could remove it again and insert a new pin effectively directly to the Nanocom.

I am thinking the problems are interference in my wiring loom and this direct connection would confirm that.
Would the Nanaocom work like this, directly plugged into the engine ECM?
Obviously i wont get access to anything other than the ECM.

What do you think?

A further issue which may or may not be related is the BeCM wont go to sleep, and this would drain the battery.
For 2 and 1/2 years i have left the car permanently on charge.
About 6 months ago i followed the check procedure in the Land Rover manual and worked through the numerous connections to the BeCM to fimnd out why BeCM would not sleep. (That took me a few days, all good fun eh?). .

Guess what i found: the pink diagnostic line K to C255 on the BeCM was keeping the BeCM awake.
I disconnected it and found to my great joy that the BeCM now sleeps after about 90 seconds on shut down, with current draw dropping form 0.8amp to a tiny 30milli volts.

Obviously with the recent Nanocom experiments i have reconnected like K to the BeCM but this "wont go to sleep" points again to a problem with Like K in the loom.

Again your thoughts please. Could the BeCM not sleeping with Diagnostic Line K connected be related to my lack of communication with the engine ECM?

Many many thanks for your guidance.

Many thanks again

Steve.

You can try wiring directly, that will take the loom out of the equation if it works. According to the BECM SID, a ground on the K line will keep the BeCM awake and, I would assume, if it is grounded then the data won't be detected either.

If you can connect with it wired directly and the BeCM sleeps, then you have found the problem. If that is the case I would simply run another wire from ECM to OBD port which should cure both problems.

Then you can get stuck in reinstating the air suspension.....

I would start by unplugging HEVAC & ABS with the K still connected to BECM & GEMS. Then see if comms works & BECM sleeps correctly. You only have 4 devices using the K-Line so try all the combos.

Once you have made a simple OBD loom, you can also connect to each ECU separately to test each one. That will require two K-line wires for the BECM, HEVAC & ABS.

Hi guys,

an update on my comms problems.

Its all good now with the Nanocom talking to the Engine ECM and the BeCM.

Your help and suggestions were bang on target. The HVAC module was causing both problems.

From my above message you will see i was worried the black ground wires on the data system were poor, and was puzzled that the resistance went up as the ignition key was turned. What a school boy error! The multimeter can only read resistance (in ohms) on dead wire. Put a current through it and it produces silly readings.

I then found the pink / red K line was showing a "leak" to ground. Only 12 K Ohms.  (with battery isolated, so all dead).

I expected to find a chaffed wire some where. Harness thoroughly inspected, carpets lifted and dash board opened up.

I systematically disconnected the Engine ECM, the BeCm and the HVAC controller from the harness and especially the pink red K Line.

This let me test the actual wiring without anything attached and proved the wiring harness, or at least the pink / red K Line was fine, with zero leak to grounds and excellent continuity along its length.

By trial and error, as you suggested, reconnecting each item in turn, the HVAC unit proved to be the cause of the leak to ground at  12 k ohms.

The engine ECM had 90 k ohm K line pin to ground resistance
The ABS unit was 250 K ohm
The Air suspension was 77 k ohm
The airbag  was 290 k ohm

It appears the HVAC was relatively leaky, and enough to keep the BeCM awake through the K Line and hinder communications between the Nanocom and the engine ECM. Do you agree this could have been the problem?

So not being too worried about the heating and vent diagnostics ( I have no  air-conditioning) i snipped the pink red K line at connector C246A.  You can get to the top of the HVAC unit if you take the radio out and wiggle your hand in.

Now the BeCM goes to sleep easily and i can use the Nanocom on the BeCM, Engine ECM, airbags, air suspension and ABS.  (I have a manual gearbox so nothing to read there).

Yippee!

Thank you for your help, the Range Rovers Pub is a real help,

Again many thanks for the guidance and suggestions.

Steve Bedder.

That must be a real base model with no AC and a manual gearbox, I thought the only ones that came with such a low spec also had the diesel engine? At least you have found the problem but your next problem is likely to be finding the correct HEVAC (the one with knobs?) for a car without AC.