Freelander 1 Autobox VSS / ABS wheel sensors

Ok, a brief history.
My 2002 133000 miles td4 ES Auto has a very infrequent fault.
Most of the time it drives perfectly. But every now and then it throws a wobbler. It can go 2 to 3 weeks between faulting.

The fault.
Driving as normal, then the rev counter and speedo will bounce around, on/off. ABS TC HDC and handbrake lights will illuminate and sometimes the engine management light. But not all of them all the time, but sometimes all of them (confused yet?)
Then either everything will return to normal and driving can continue, or the gearbox will go to F4 limp mode.
So pull up, switch the engine off, count to 10, restart, and off we go. Sometimes it will be fine for another 2-3 weeks, other times it will do it every 15-20 minutes until it's left for an hour or so.
Fault codes are P0500 (vehicle speed sensor) and various can bus errors saying that the ABS cannot communicate with the tcm and there is no coms to the instrument binnacle.

Using the Icarsoft LR2 code reader shows all abs sensors are working. Communicating with the TCM is hit and miss with this reader but the VSS just reads error constantly, but I can't say if this function works or not. All coms that do work with the TCM read ok, but quite a few won't show anything. Communication to the instrument binnacle says it's not there!!!
So that's not a great help.

So does the rev and speedo work off the ABS feed or the VSS feed or both?
Does the camshaft sensor have any input into this?

I'm going to clean all the ABS sensors and the 2 multi plugs from the autobox. Also the ABS connection to the ecu.
There are no obvious cable issues or worn connectors. But as it's an old car I'm aware that it could also be a moisture issue in some way.

Any ideas or thoughts would be appreciated.
Or if you want more info just ask.

Mike

My ABS light on the dash has been playing up since I got it back after MOT in January this year. Been meaning to get it fix. I understand the reluctant ring is worn and causing the sensors to malfunction. I would give them a a check an clean first. I notice a difference compering the speedo versus satnav on the motorway about 70mph

it sounds as though you have a loose connection do a search on here as I am sure Hippo covered it the connectors you are looking for I think on top of the gearbox
hope this helps

saxavordian said:

My ABS light on the dash has been playing up since I got it back after MOT in January this year. Been meaning to get it fix. I understand the reluctant ring is worn and causing the sensors to malfunction. I would give them a a check an clean first. I notice a difference compering the speedo versus satnav on the motorway about 70mph

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Cheers, will get the head torch on and check them out.

teddywood1 said:

it sounds as though you have a loose connection do a search on here as I am sure Hippo covered it the connectors you are looking for I think on top of the gearbox
hope this helps

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Cheers Teddy, your quite correct, I've read that thread a couple of times. I'm going to give those barrel connectors a good going over, they are a bad design.


The thing what baffles me, is where does the speed signal actually come from? And what's feeding the rev counter?

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Mike

Skinny Mike said:

Cheers, will get the head torch on and check them out.



Cheers Teddy, your quite correct, I've read that thread a couple of times. I'm going to give those barrel connectors a good going over, they are a bad design.


The thing what baffles me, is where does the speed signal actually come from? And what's feeding the rev counter?

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Mike

Click to expand...

doesn't the ecu work out the speed signal that it receives from the 4 x sensors

plus wasnt there something about the sensor that sits by the handbrake , the ecu compares this with the abs sensors to ensure they are at equal speed results

wasnt it called a g sensor

Rev counter comes from the engine ecu

My first impression reading your description is that the car looks to be resetting itself and getting confused on the reset because everything's operating/turning etc. Sort of ties in with Teddywood's connection suggestion - I'm thinking the ignition switch is borderline total failure.

gstuart said:

doesn't the ecu work out the speed signal that it receives from the 4 x sensors

plus wasnt there something about the sensor that sits by the handbrake , the ecu compares this with the abs sensors to ensure they are at equal speed results

wasnt it called a g sensor

Rev counter comes from the engine ecu

Click to expand...

Will look that up about the g sensor. The confusing thing is there's 3 speed sensors in the autobox, 2 can be discounted, but the 3rd the vehicle speed sensor, is that just for the tcm for gear changes or is it going to the speedo.
Yes the ecu gives the revs, but Where's it's data actually coming from?
Mike

The dash could have a dodgy connection. The dash is used as a connection point to lots of other ECUs. Everything talks on the K line bus, using the dash as the connection point. That's where I would start looking.
There are instances of the ABS ECU messing up other ECUs it's connected to it too.

Skinny Mike said:

Will look that up about the g sensor. The confusing thing is there's 3 speed sensors in the autobox, 2 can be discounted, but the 3rd the vehicle speed sensor, is that just for the tcm for gear changes or is it going to the speedo.
Yes the ecu gives the revs, but Where's it's data actually coming from?
Mike

Click to expand...

The vehicle speed is derived from the ABS sensors, worked out by the ABS ECU, then sent as data on the K line bus to the instrument cluster (I Pack).
The speed sensors in the box are there to give the TCM information so the box change points can be worked out.

Nodge68 said:

The dash could have a dodgy connection. The dash is used as a connection point to lots of other ECUs. Everything talks on the K line bus, using the dash as the connection point. That's where I would start looking.
There are instances of the ABS ECU messing up other ECUs it's connected to it too.

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Hello Nodge

I've had the dash to pieces before but couldn't see anything obvious, but I have new reading glasses now!! So should be able to check it better.

The other thing that springs to mind is that the binnacle emits a high pitch tone (beep) when this fault occurs, barely audible. Relevant???

Mike

Skinny Mike said:

Hello Nodge

I've had the dash to pieces before but couldn't see anything obvious, but I have new reading glasses now!! So should be able to check it better.

The other thing that springs to mind is that the binnacle emits a high pitch tone (beep) when this fault occurs, barely audible. Relevant???

Mike

Click to expand...

Could be relevant tbh. I suspect that there's something up with the Ipack. It sounds like a glitch with it anyway.

Nodge68 said:

The vehicle speed is derived from the ABS sensors, worked out by the ABS ECU, then sent as data on the K line bus to the instrument cluster (I Pack).
The speed sensors in the box are there to give the TCM information so the box change points can be worked out.

Click to expand...

Excellent, that's what I need to know.

So looking more towards a CAN error somewhere, probably binnacle.

But will still do all other checks.
Mike

Nodge68 said:

Could be relevant tbh. I suspect that there's something up with the Ipack. It sounds like a glitch with it anyway.

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So, check instrument pack, cables, wires, soldering etc.

ABS reluctor rings and sensors.

Autobox barrel connectors.

Bosch ABS multi connector.

ECU connector.

GrumpyGel said:

My first impression reading your description is that the car looks to be resetting itself and getting confused on the reset because everything's operating/turning etc. Sort of ties in with Teddywood's connection suggestion - I'm thinking the ignition switch is borderline total failure.

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And the ignition barrel

Should keep me occupied

Thank you guys
Any more ideas, please put them up
Mike

are the battery terminals tight and clean

It's strange that the Icarsoft won't communicate with the Ipack. My I930 connects to my Ipack but because my TD4 is a facelift, the I930 can't do anything with it. It does connect to it though as all the lights come on and the gauges swing full over then back, before the I930 says no faults logged.
My I930 won't communicate with the TCM however. It just says "communication failed" whenever I try to read the box codes.

Nodge68 said:

The vehicle speed is derived from the ABS sensors, worked out by the ABS ECU, then sent as data on the K line bus to the instrument cluster (I Pack).
The speed sensors in the box are there to give the TCM information so the box change points can be worked out.

Click to expand...

thks, appreciate u explaining it better , I knew basics but not in great details

Skinny Mike said:

So, check instrument pack, cables, wires, soldering etc.

ABS reluctor rings and sensors.

Autobox barrel connectors.

Bosch ABS multi connector.

ECU connector.



And the ignition barrel

Should keep me occupied

Thank you guys
Any more ideas, please put them up
Mike

Click to expand...

hope u get it sorted out mate , nothing worse in driving u nuts with regards to electrical faults

will be interesting to see how u get on and what u find out

daft question , can a failing fuel pump , filter cause the hippo to go into limp mode as it sends a message to the engine ecu ??

Nodge68 said:

It's strange that the Icarsoft won't communicate with the Ipack. My I930 connects to my Ipack but because my TD4 is a facelift, the I930 can't do anything with it. It does connect to it though as all the lights come on and the gauges swing full over then back, before the I930 says no faults logged.
My I930 won't communicate with the TCM however. It just says "communication failed" whenever I try to read the box codes.

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It does the lights on bouncy gauge test, but if you select instrument pack it fails to connect.

terr said:

are the battery terminals tight and clean

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Brand new shiny battery with clean terminals.

gstuart said:

daft question , can a failing fuel pump , filter cause the hippo to go into limp mode as it sends a message to the engine ecu ??

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Yes, a blocked filter or dodgy pump can cause limp mode, but they're both ok

Will just have to logically go through stuff. My current thinking is either the instrument pack or the ABS unit has a fault.
As

Skinny Mike said:

It does the lights on bouncy gauge test, but if you select instrument pack it fails to connect.

Will just have to logically go through stuff. My current thinking is either the instrument pack or the ABS unit has a fault.
As

Click to expand...

I think that the gauges bouncing with lights on is connected on the data bus. The Icarsoft doesn't seem able to actually talk to the Ipack in the correct language, once it's connected. It's the equivalent of me phoning a number in Japan and then not understanding what they are saying, when they answer.

I'm thinking that the ABS ECU or Ipack could be at fault. Both can do the odd things you are experiencing.

I'd change the ABS ECU first as it doesn't need coding to the car.