Error code C1A96

[shining]

Hi Oh Great Brains Trust

Any clues on this Transmission Fault. I love living in a town without a dealer!

[disco4now]

I see C1A96-64 under ABS faults;

Brake Light Switch Plausibitity Fault

Check the Stop lamp Functions. Ensure brake lamp switch is correctly installed and configured.

Not sure if it helps, just happened to have the codes handy.

[seano87]

Quick google of the code suggests its a brake system code. Main ideas seem to suggest checking your brake lights as a blown bulb can cause it - some suggesting you need genuine LR bulbs to make it happy again, also check the brake pedal has returned to the correct position/switch reseated by giving the pedal a "firm" pull back as it may have just not returned correctly after de-pressing.

Hope that helps.

[seano87]

Haha too slow of me! Good to see we have both suggested the same thing though.

[shining]

Thanks guys. I have got a fault code unit. Funny thing was I was getting a transmission fault, suspension lowered, no sports or command shift, seemed to have all gears though.
C1a96 is the only fault that was showing.???
Cheers

[Jamo]

It's probably the brake light had gone and the element has shorted onto the tail light element. for some reason this has been known to affect the suspension...A weird computer glitch.

[bbyer]

It's probably the brake light had gone and the element has shorted onto the tail light element. for some reason this has been known to affect the suspension...A weird computer glitch.
The link below is to my Gallery file section on disco3 where I have put some files related to the brake light circuits. One of the files is the brake wiring diagram.

If one looks closely, you can see how the brake lights are tied to the ABS module and more interestingly, the reverse lights via a common ground within the tail light fixture assembly. As a result of that common ground, then back to the transmission via a reverse gear relay; also the brake light power feeds back, (or not), to a hill decent relay which tends to explain why we get a HDC failure message when all it is is something to do with the brake circuit.

If one still has the original LR brake light switch installed, (the blue and white thing in the attached pdf), it would probably be a good idea to install the newer FOMOCO updated switch. It costs about twenty dollars and is actually fairly easy to replace, (even the first time).

DISCO3.CO.UK Photo Gallery - Brake Light Switch Replacement (http://www.disco3.co.uk/gallery/thumbnails.php?album=5082)

[shining]

I had a look this morning, although it was very (insert expletive) cold (relatively speaking bbyer ;-), hope you have a comfy chesterfield).

Brake lights functional. Got it to recur once only. I only had a quick look at the earths. If that were the problem then perhaps would I be seeing other faults as well? If the brake switch is intermittently faulty then this only symptom I will see?

Its great having a brains trust!

[shining]

Update.

I removed the brake light switch, disassembled, cleaned and got another 600kms out of it before failing again. I assume that the black powder from the shaft wear was sticking to the lubricant on the contacts causing the "comparison failure". The replacement switch arrived in the meantime and I have just refitted. I will provide a final update after a few more kms.

[Scouse]

I believe the brake light switch fault can also be triggered by left foot braking.

If you brake with your left foot & accelerate with your right, any overlap can confuse hell out of the computers & they'll think the brake switch is at fault.

[101RRS]

Another example of making these cars complex than they need to be - sorry some people drive like that - it is starting be do what the car wants - not what you want.

Garry

[oldsalt]

Replace your brake light bulbs (plus others) with LED ones and you take one piece out of the equation .... here's a good place to get 'em.
Xenon HID Headlight Upgrade Kits from HIDS 4U - H7, H4, H1 (http://www.hids4u.co.uk/home.php)

cheers

[shining]

I must admit with big boots on my big feet I have hit the brake and accelerator at the same time.

[bbyer]

I believe the brake light switch fault can also be triggered by left foot braking.

If you brake with your left foot & accelerate with your right, any overlap can confuse hell out of the computers & they'll think the brake switch is at fault. That is an interesting thought.

Heel and Toe braking/acceleration used to be a standard race car driving practice, and in some quarters, street driving as well. Even though I regard the 3 as part Race Truck, I would doubt LR would have designed for the possibility of both the brakes and accelerator being pushed at the same time. Maybe though, as when you are stuck in the snow, in the past with an automatic, often you have to get a spinning wheel to stop while you add power - maybe the anti-slip does that now but...

Toyota is as a result of recent concerns, introducing an interlock between the brake and accelerator pedals such that braking action overrides engine acceleration. I wonder how they are triggering the system? The brake switch would seem to be the easy way so I wonder what additional concerns might evolve.

I do understand other manufacturers already have the interlock on many of their new designs so I suppose Toyota will just copy one of those designs, hence I wonder just what signal triggers them.

I would say my 2005 LR3 does not have the interlock as I experimented a few months back when all this was in the news just to see if the interlock was already incorporated.

[Graeme]

Thanks guys. I have got a fault code unit. Funny thing was I was getting a transmission fault, suspension lowered, no sports or command shift, seemed to have all gears though.
C1a96 is the only fault that was showing.???
Cheers
The suspension system is programmed to lower the suspension to a safe height (about access height) for any fault issued by ABS.

[Ashes]

That is an interesting thought.

Heel and Toe braking/acceleration used to be a standard race car driving practice, and in some quarters, street driving as well. Even though I regard the 3 as part Race Truck, I would doubt LR would have designed for the possibility of both the brakes and accelerator being pushed at the same time. Maybe though, as when you are stuck in the snow, in the past with an automatic, often you have to get a spinning wheel to stop while you add power - maybe the anti-slip does that now but...



Not sure that statement is true. A very legitimate driving technique for steep downhill descents (without using the HDC mode) is to brake reasonably hard with the left foot and then drive through the braking with the accellerator to keep slow but controlled downhill momentum.
I've done this on training days with no adverse affect or error codes coming up.

I have though had the faults listed above on an irregular basis with nothing ever being found and it always clears itself after a few restarts.

[bbyer]

Not sure that statement is true. A very legitimate driving technique for steep downhill descents (without using the HDC mode) is to brake reasonably hard with the left foot and then drive through the braking with the accelerator to keep slow but controlled downhill momentum.
I've done this on training days with no adverse affect or error codes coming up.

I have though had the faults listed above on an irregular basis with nothing ever being found and it always clears itself after a few restarts.Yes I agree, one foot on brake and the other on the accelerator tends to work on two wheel drive going uphill to keep a wheel on one side from starting to spin; also when stuck with an automatic RWD and I guess a FWD as well - but not much experience with that.

Once all these safety interlocks become standard, about all one will be able to do is move forward in paved dry surfaces unless maybe you have a Land Rover.

[stig0000]

are you actuly getting eny lights on the dash or just getting a code with no sympoms,

[Scouse]

Not sure that statement is true. It doesn't happen all the time but it does happen. Would a Land Rover bulletin convince you?






ReferenceSSM48997ModelsDiscovery 4
Discovery 3
Range Rover Sport
TitleDTC’s P0504-00/27/62, P0724-17 and C1A96-64 CategoryDriveabilityLast modified15-Apr-2011 00:00:00Symptom614000 Lack/Loss of PowerContent
Issue:
Customer complains that various warning lights (ABS, DSC) illuminate on the instrument cluster, the cruise control system may also be inoperative. Upon diagnostic investigation some of the following DTC’s maybe stored P0504-00/27/62, P0724-17, (PCM) and C1A96-64 (ABS ECU).
NOTE: DIESEL only – Engine system fault maybe displayed on the instrument cluster message centre, warning the driver that the engine has gone into restricted performance mode. This can be cleared by cycling the ignition.
Cause:
1) Left foot braking/resting left foot on the brake pedal then applying the throttle pedal whilst the left foot is still on the brake pedal. This may result in warning lights illuminated on the instrument cluster and for DIESEL models maybe accompanied with an engine system fault message displayed on the instrument cluster message centre.
2) Brake pedal position switch set incorrectly or brake switch circuit concern, i.e. the switch is detecting the brake pedal is applied when it is not. This will result in warning lights illuminated on the instrument cluster with no other symptoms evident.
Action:
Should a customer express concern regarding the above stated issue please check the integrity of the brake switch circuit and carry out the Brake Pedal Position (BPP) switch check (the specification is that the stop lamps should illuminate at between 5.5mm and 8.5mm brake pedal travel), refer to TOPIx Workshop Manual section 417-01 > General Procedures > Brake Pedal Position (BPP) Switch Adjustment.
NOTE: If the brake pedal switch specification is found to be out of tolerance please record the brake travel measurement and submit a Quality Concern EPQR. To allow consistent collection of data please submit the EPQR under Module - engine control, Engine lacks power will not accelerate as expected.
If the brake switch is correctly set and no issue is identified within the brake switch circuit then the concern is likely to be associated with the driver left foot braking/resting their left foot on the brake pedal whilst then applying the throttle pedal.
PLEASE NOTE - It is not good driving practice to ‘apply’ the brake pedal with the left foot. The driver of the vehicle should be advised to use the left foot rest adjacent to the brake pedal to avoid further potential occurrences of this problem in the future.

[Graeme]

PLEASE NOTE - It is not good driving practice to ‘apply’ the brake pedal with the left foot. The driver of the vehicle should be advised to use the left foot rest adjacent to the brake pedal to avoid further potential occurrences of this problem in the future.
...in the opinion of someone at LR anyway.

IMO LR does a lot worse by limiting power and lowering the suspension if the above is done. The problem only exists because LR give a higher priority to detecting a possible faulty brake switch than to allowing advanced driving techniques.

[shining]

I was getting both the error message on the display and the two warning lights ABS? and DSC?

[shining]

Update.
Touch wood...all OK now. I haven't done too many kms but the error hasn't recurred since changing the brake switch. Thanks to all for the info.

[dangermousehouse]

Hi Shining,

Just catching up with this thread.

I had very similar problems with mine, which also turned out to be the brake switch.

Other 'problems' which can this fault are -

1 - Broken brake bulb filament. The bulbs have 2 filaments and if one breaks it can come into contact with the other filament and cause an earth.....which then causes the associated tin brains to have a seizure. The bulbs should be mounted so that the filaments are vertical and not horizontal.

2 - Steering wheel alignment. If your steering wheel isn't straight when driving straight, then this can also cause a seizure.

3 - Brake switch itself.

Did the problem happen when slowing down and braking?

Anyways, the above info' was collected from better minds whilst I was investigating my fault.

Hopefully your fault has been solved, now, though.

Cheers

[shining]

Hi DMH,

I had hoped it was the brake lights as that would have been the easiest to fix. But the brake switch is only a little harder. As I was waiting for a replacement switch I did disassemble the brake switch and clean it up. I got about 500kms out of it. I think the error did happen when using the brake but could not be absolutely sure. I reckon this forum is the best thing since sliced bread. Not only for the D3 but for everything LR.
Cheers.