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LEGACY VENDOR
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1,108 Posts
Discussion Starter #1
Dash Displays:
HDC Inactive
Air Susp Inactive
ABS Light on
Brake Light On

Pulled Fault Codes(using my own home grown tool so may at this point be inaccurate)
IP modules: EBV function fault received from ABS ECU
ABS module: ABS return pump Fault
ASU module: Can Bus Fault
ATC module: Aspirator motor fault

Steps Performed
Tried to reset Steering angle sensor several times. (start engine. Turn wheel to right limit then to left limit)
Inspected abs wheel speed sensors.
The faults will self clear from time to time and then come back seemingly for no reason.

Possible related events
Vehicle was at body shop for two weeks and battery was probably dead.
Battery has since been charged by myself a couple of times overnight.
Just went off roading for about 2 hours. Seemed to trigger ABS and brake light. where previous it was just HDC inactive and Air Susp Inactive.

The faults are really a blessing in disguise as it is extreme motivation for me to communicate with the Rover subsystems for the fault codes.
 

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LEGACY VENDOR
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1,108 Posts
Discussion Starter #2
The ATC module Fault:
Aspirator motor fault

Is unrelated. I thought that the ATC was Automatic Transmission Control. Although on further research, I see that it has something to do with the Cabin Temperature Control. The failure of the aspirator motor would explain why the temperature controls have no effect on the insane ammount of cold air blowing from the Dash vents.

Does anyone know what the "EBV function fault received from ABS ECU" code is all about?
 

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LEGACY VENDOR
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1,108 Posts
Discussion Starter #3
I hate to do a 3 peat, but a few things changed. I just stared the vehicle and there were no dash messages. I queried the faults and this is what I got;

IP modules: EBV function fault received from ABS ECU
ASU module: Can Bus Fault

The two fault were logged but could be sucessfully cleared (big change from previous). The third ABS return pump fault was not logged.
The ABS Pump fault is gone. Was the ABS return Pump the intermittent cause of all the problems?
 

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35 Posts
Many here know a lot more than me about this, but FWIW: As I understand it, a can bus error means that two or more computers were not communicating with each other. Each time this has happened to me, the issue has been low voltage, such as after the truck has been started on a weak battery.

The faults you see on your dashboard are all from interrelated systems that rely on plausibility tests to work together, for example HCD would shut down if it thought the ABS wasn't working, ABS would shut down if a wheel speed sensor seemed out, etc. My understanding is that this is why a can bus error can cause a cascade of system problems.

Only twice did this not turn out to be a voltage problem with mine. One was a loose chassis ground, and the other was a failed wheel speed sensor.

Anyway, good luck.
 

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LEGACY VENDOR
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1,108 Posts
Discussion Starter #5
After some further research, I am finding out from my local LR mechanic, that the MKIII is an absolute terror about random faults.

More research revealed that the MKIII uses a distributed type of information network. In that there is no centralized or dedicated module for information distribution. All information distribution is performed over the CAN bus. There are no dedicated wires for each signal. The CAN bus carries all of the traffic. For example, modules such as the ABS module will spew out information packets on vehicle speed. And all of the other modules that need that information will simply listen on the CAN bus and read that packet when it comes across. Several modules on the CAN bus will listen for and pickup that speed packet. The EAS and the Hill descent Control for example would need that information.

Imagine the CAN bus as a overpacked busy busy room where a very loud party is going on. It would be difficult and unecessary to listen to all of the conversations. You only need to listen to the conversations that are intended for you. If that information is disrupted then the system goes into a fail safe. Luckly the fail safe can be a temporary condition.
 

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10 Posts
Had a similar problem recently, included entertainment system shutting down, starting up, engine spluttering occasionally. Ended up with flat battery a couple of times and got the RR jumped. Turned out to be the alternator was failing and supplying too low a voltage to run the systems in the RR and had no spare juice to charge battery. Alternator was reconditioned by local engineering firm and all perfect now. Seems the BMW based TD6 has some alternator issues with higher mileage; alternator repair guys say they do a lot of these repairs. Much cheaper than getting new item fitted. Worth checking voltage of running engine, I seem to remember that it should be producing more than 14 volts to power systems and charge battery.
 

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LEGACY VENDOR
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Discussion Starter #7
The alternator and the battery have both been replaced within the last 10 thousand miles. I also just recently had the vehicle on the charger each night before the problem happened. The battery was on the charger because I was working with my laptop alot with the engine off.

I think that the problem originated in the HDC system. The fault, "ABS Return pump" is a component of the HDC system. It is clear to me that most of the faults on the EAS are not going to be specific to the EAS, but rather a different subsystem causing a more systemic failure. If the EAS is in soft fault mode and locks the suspension out accompanied by other system faults, I think the problem is in another system. Now if the EAS went into hard fault mode, then this would indicate most probably that something in the EAS is truely broken, i.e...a height sensor or such.

Although, on the other hand, a simple failure of the vehicle speed signal would cause the same malfunction in all three systems. So maybe it is simply a CAN bus failure where the speed signal was lost. I am not sure yet.
 

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1995-2002 Range Rover P38A
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Malafax_dand said:
The alternator and the battery have both been replaced within the last 10 thousand miles. I also just recently had the vehicle on the charger each night before the problem happened. The battery was on the charger because I was working with my laptop alot with the engine off.

I think that the problem originated in the HDC system. The fault, "ABS Return pump" is a component of the HDC system. It is clear to me that most of the faults on the EAS are not going to be specific to the EAS, but rather a different subsystem causing a more systemic failure. If the EAS is in soft fault mode and locks the suspension out accompanied by other system faults, I think the problem is in another system. Now if the EAS went into hard fault mode, then this would indicate most probably that something in the EAS is truely broken, i.e...a height sensor or such.

Although, on the other hand, a simple failure of the vehicle speed signal would cause the same malfunction in all three systems. So maybe it is simply a CAN bus failure where the speed signal was lost. I am not sure yet.
Wow!

Nice to see you really getting into it!

:)
 

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2002-2005 Range Rover MkIII / L322
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183 Posts
A couple of months ago, I started having this message randomly. A couple of times I checked with my All Comms, and the only thing that came was: CAN bus fault.
Tried disconnecting the battery a couple of times, but probably after half an hour of driving, it showed again. Then I found that switching off the car completely, and starting it again, will make the message disappear temporarily.

But then I started to connect the dots. I bought this Range 2 years ago with only 8k miles on it. At times during the first 5 years, it had sat with the tires flat for weeks and months at a time, since the owners lived overseas. In December, on a long trip, one of the rear tires deformed out of the blue while travelling on the highway for over 6 hours. Never hit anything. Since I carry an infrared thermometer all the time, this tire was about 10 degrees F more than the others. The thread, instead of being flat had developed a bump around the whole circumference. Put the spare and everything ok. On the trip back, a slight vibration developed on the rear right side, but nothing big. At this stage, no messages had developed yet.

Took the car to have the tires balanced some weeks after that, and the attendant told me that the rear tire had suffered some deformation, and although he had balanced, the car will probably show some sort of vibration. Sure enough, the vibration remained, and the message in the panel came almost every of the few times that I used the car.

By this time, I was almost sure that the HDC and Air Susp Inactive with ABS and Lights will disappear from the message board, just by changing the tires. By the way, the original tires were Dunlop Grandtrek ST 8000, with only 26k miles on it, and half the thread still there. Last week I installed Yokohama Parada Spec-X tires at the Land Rover dealership (tires from TireRack). Had an alignment done at the same time. Nothing else was done there, since I didn't mention the message problem. I wanted to correct it myself.

Sure enough, the message has disappeared totally.

My only explanation is that the continued micro-oscillation of the suspension due to the defective tire, was triggering this problem, because probably the computer lost sequence of the instant readings from the height sensors. I hope somebody in this forum can provide with the right explanation, and hopefully anybody can benefit from a case like this.
 
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