Computer / False Error Codes on RRS - 2016

392 Views 18 Replies 6 Participants Last post by RichMcM, 1 h ago

RichMcM

Discussion Starter · 7 d ago

My RRS has developed a recurring problem with the message warning.

Although all is well with the car, after about 10; minutes driving I usually get an Amber Warning Message statin: “ Only Normal Height Available“.

I cancel the message and then find that the Forward Warning System stops working and the Cruise Control cannot be activated. That aside, the car runs normally but it’s very frustrating for long journeys etc.

The car has been checked using the Land Rover diagnostic equipment and the only fault that is saved suggests a communication problem. The Land Rover Diagnostic Specialists have advised my engineer to have the car back to complete an online check of the system. Having dealt with the Specialists in the past, I have low levels of confidence in their ability to fi the problem. Indeed, I fear that they will propose a frenzy of spare parts leaving me with high bills and no solution.

I wonder if anyone has encountered similar problems - car driven 65k - and can offer advice.

Thanks

Rich McM

1 - 19 of 19 Posts

NoExpert

· #2 · 6 d ago

Knowing exactly what the code is and what is losing comms is pretty helpful.

Could be as simple a dying battery not able to push enough power for all the systems. Start there, get a proper test for CCA and voltage as well as what power the alternator is pushing.

You need somebody to pull live data from the Ride Level Module (RLM); sensor heights, galley pressure, reservoir pressure, etc. Then go for a drive and see what goes haywire after about ten minutes. Could be a height sensor sending an erratic signal or a slow leak between the compressor and reservoir. A lot of variables, but that’s where I’d start.

RichMcM

Discussion Starter · #3 · 6 d ago

Thanks ‘NoExpert’ - I didn’t make myself clear.

First, the battery is about 6 months old having been replaced to fix the Stop/Start problem. It works perfectly now.

Second, the problem is not with the suspension as on some days I can drive for an hour without issue.
The problem codes only highlight a communications problem with the Comms Hub probably the cause.

I was hoping to hear from someone with either similar experience or knowledge of this issue.

Any tips highly appreciated

NoExpert

· #4 · 6 d ago

Well, without knowing the code(s) it’s hard to say where to focus the effort in the communications chain.

You say the suspension works fine, but obviously something there isn’t right and it’s dropping comms with the RLM.

I work on these cars for a living, so I know a little of what I’m talking about.

RichMcM

Discussion Starter · #5 · 6 d ago

Thanks - I wasn’t doubting your expertise, just did not make my problem clear.
I’m anticipating advice from the LR diagnostic team (DT) but was hoping to hear of others experience.
Reason for my distrust of the DT is they recommended a new arm for my rear door when the automatic closure stopped working. Someone advised cleaning the rear parking sensors and I saved over £300.

NoExpert

· #6 · 6 d ago

I know exactly what you mean, some places follow the codes to a T and just replace what they think the codes point to. That’s why I suggested getting live data, helps rule things out. If it was a bigger comms issue you’d get more faults.

The biggest issue with diagnostics is half the time the system just makes a guess and throws a code. It isn’t programmed for every scenario, like dirty parking sensors. This is where knowing exactly what the code is makes a big difference since it may correlate to something else actually causing it.

RichMcM

Discussion Starter · #7 · 6 d ago

The reason I’m confident it’s a Comms problem is because other systems such as Cruise & Forward Warning stop working once the Amber ‘suspension fault’ triggers.

If I get the codes, I’ll share on this thread.
Thanks for engaging.

GeorgeBuhr

· #8 · 6 d ago

As NoExpert said, codes really help with providing a diagnostic road map. If it is a communication problem, it is important to see which module is actually not communicating. Getting a message for only normal height available does not mean there is a problem with the suspension. It means there is a problem SOMEWHERE, that is causing the module to lock out any other mode than normal height. If cruise and forward warning stopped working, maybe by those not working it is causing the ride height lock out. Or, it could be something as simple as for example, maybe you ran over something in the road, and it hit the radar sensor in the front just enough to knock it out of alignment, and it now needs re-calibrated, which is why it no longer works, but as a result of being disabled, it also disabled the ride height. Again, I would love to see what codes you have because it is tough to know where to even start otherwise.

I would also question which battery you replaced. Was it the auxiliary battery, or was it the main battery? If it was the auxiliary battery, that would affect the start stop, but shouldn't affect anything else. What I am getting at, if you replaced the aux battery only, how do you know that the main battery is not low as well, yet has enough juice to start the car, but not enough to keep the voltages steady in the control modules enough to avoid kicking off false codes?

You can see where this can go multiple different directions without any codes.

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RichMcM

Discussion Starter · #9 · 6 d ago

Thanks GeorgeBuhr - as you say, it’s complicated.
Before getting the “Normal Height” warning, both cruise and forward warning work perfectly. So I suspect that when the Comms trip, it affects the all the systems but only notifies the height warning.

Re the batteries -. I was not aware of the Aux battery. However, once I had installed a new main battery, the Stop/Start has functioned perfectly. I wonder if an old Aux battery could affect the Comms problem?

Thanks

GeorgeBuhr

· #10 · 5 d ago

The soul purpose of the auxilary battery is to keep all the computers alive while engine is shut off, so that they do not have reboot themselves during the recrank on the starter, which normally causes the voltage to drop below 11 volts. The auxillary battery helps keep the voltage drop separated, so you do not get the inevitable problem that would occur during recranking each time. However, if the auxillary battery ever fails, the car will just not shut off at the stop lights, basically disabling the auto stop on its own.

Reactions: 1

RichMcM

Discussion Starter · #11 · 5 d ago

4

By way of an update, I’ve attached 4 photos which cover the fault codes.
For the experts, I’m told that they are not very helpful.

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GeorgeBuhr

· #12 · 5 d ago

I agree, unfortunately thats going to take some digging into from someone that is good with diagnosing wiring issues. They should be able to probe the can wires on the different modules and scope the signal, which might give an indication whether one is sending or receiving proper data. I have seen Diagnose Dan on YouTube do this many times.

Reactions: 1

NoExpert

· #13 · 5 d ago

I think I’d attempt to reprogram the TCM by telling the system a new module was installed. Then see if anything changes.

karlp606

· #14 · 4 d ago

Id second what NoExpert has said here. He is an oracle of Land Rover knowledge certainly helped me out a few times.
Also just putting it out there you could buy a 2nd hand gear terrain module from ebay swap yours over (can be done yourself within an hour and doesnt need any coding) and see if this fixes the TCM fault

Like here

www.ebay.co.uk

Range Rover Sport L494 Terrain Response Air Suspension Traction Control central | eBay

Find many great new & used options and get the best deals for Range Rover Sport L494 Terrain Response Air Suspension Traction Control central at the best online prices at eBay! Free delivery for many products.

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Tyrnbiter

· #15 · 2 d ago

With your battery recently being replaced I'd have another look at it. The ten minutes to failure suggests a spotty connection. If the battery terminals and connecting cables were not properly cleaned the connection either post can be faulty to where it is only a pin-point. In operation the point of connection will heat up and resistance will increase. It seems common practice in the U.S. to install a new battery without any attention to the terminals. If the posts are grey clean them until there is clean metal to connect to. Additionally, smearing grease ( plain axle, or wheel bearing ) all over the terminals and top of the battery seems to have become common. The dealer put so much grease on my daughters Subaru's battery during a scheduled service recently that the second morning after the "service" it was dead. Roveritis, an indulgence to be sure, is inclusive of the pit of the stomach feeling to suspect the complexity of the vehicle when things are not quite right. I would hope the situation could be corrected with a solution as simple as suggested.

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RichMcM

Discussion Starter · #16 · 2 d ago

Thanks - I’m seeing the diagnostic guys next week - I’ll throw in all the suggestions

Jh972

· #17 · 1 d ago

GeorgeBuhr said:
The soul purpose of the auxilary battery is to keep all the computers alive while engine is shut off, so that they do not have reboot themselves during the recrank on the starter, which normally causes the voltage to drop below 11 volts. The auxillary battery helps keep the voltage drop separated, so you do not get the inevitable problem that would occur during recranking each time. However, if the auxillary battery ever fails, the car will just not shut off at the stop lights, basically disabling the auto stop on its own.

Not exactly correct (being a pedant I admit). The purpose is to power all the all the computers rather than the main battery, so that they don't endure spikes when the engine stop/starts. Not when the engine is shut off necessarily.

Reactions: 1

RichMcM

Discussion Starter · #18 · 1 d ago

About to lubricate the Main Battery Terminals just to remove that concern.

RichMcM

Discussion Starter · #19 · 1 h ago

2

RichMcM said:
Thanks - I’m seeing the diagnostic guys next week - I’ll throw in all the suggestions

I’ve checked the battery terminals and all looked fine & tight.
I did find one disconnected cable but was unable to find the missing link. Any ideas very welcome.

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