Member Since: 03 Nov 2017
Location: Bristol
Posts: 9
C1A07 Fault Code
Hi everyone. I appreciate that the D3 forum has quite a few post on this topic but they are from quite a while ago so thought it best to start a new one.
So I have C1A07 "Cross Articulation Algorithm Failure" - "Signal Compare Failure" fault code. Then also with the MAXSPEED 30mph on the dash and the suspension dropping to the bump stops. Switching off the engine and restarting clears the problem temporarily. I have one stretch of local A road where this will occur 10 times in a matter of 2 miles so virtually impossible to drive anywhere. It seems to only appear when driving above 40 or 50 mph and on A roads that have dips and troughs in them at irregular low frequency intervals that cause the rear of the car to sit down momentarily as it passes over them. Driving on similar road surfaces but below 50mph is no problem as the fault does not appear. I had to install 2 new rear height sensors last week due to one of them going out of range for adjustment (1 rear corner height was way too high @520mm and couldn't be adjusted down) and previously to that I had no problem at all.
I've checked voltage input and voltage output to and from the height sensors and can't see anything amiss. After fitting the sensors (both genuine LR parts from same source not OEM replacements) I calibrated the corner heights to ensure they were all within tolerance - all details below:
Input voltage for all sensors = 4.91v
Output voltage for each sensor at "Normal Height" is:
FL = 2.63v, FR = 2.90v, RL = 3.03v, RR = 2.55v.
Measured wheel heights (centre to arch at "Normal Height") in mm are:
FL = 470, FR = 465, RL = 485, RR = 485.
Suspension height changes operate correctly with no issues, and there are no other faults or fault codes on the vehicle.
If anyone has any suggestions as to how to solve this annoying problem I would be very grateful to receive them. Cheers.1967 Series-2 2.0l petrol
1984 Range Rover Vogue 3.5 V8
1993 Discovery 1 200 7 seater
1998 Discovery 300
2003 Discovery D2 TD5 7 seater
2010 Discovery D4 3.0l 7 seater.
20th Sep 2020 2:00 pm
dgardel
Member Since: 03 Nov 2009
Location: Greater Venice
Posts: 2025
Voltage are ok.
Try with a full re-calibrationDiscovery 5 tdv6 HSE Corris Gray Outback Engineering Limited Edition IID Pro MV License
20th Sep 2020 6:48 pm
dgardel
Member Since: 03 Nov 2009
Location: Greater Venice
Posts: 2025
Double post sorryDiscovery 5 tdv6 HSE Corris Gray Outback Engineering Limited Edition IID Pro MV License
20th Sep 2020 6:49 pm
Boede
Member Since: 03 Nov 2017
Location: Bristol
Posts: 9
Hi dgardel, Thanks for the response - much appreciated.
I have spent quite some time (over several days) trying to level up the suspension to get the correct ride heights. I am using a Nanocom EVO2 which only has the facility for adjusting individual corners manually so it becomes a bit of a guessing game trying to understand what effect changing one corner will have on the other 3. However, I thought that I had managed to get the 4 corner heights close enough to the nominal that the system would accept them without moaning about it. Do you know how close they have to be to the nominal measurements (wheel heights or sensor voltages) such that the system is happy with them? I'm not sure I can improve on what I've achieved so far with the Nanocom. Assuming that I've run out of options to improve anything in this context do you know of any other better options other than visiting a main dealer? Cheers.1967 Series-2 2.0l petrol
1984 Range Rover Vogue 3.5 V8
1993 Discovery 1 200 7 seater
1998 Discovery 300
2003 Discovery D2 TD5 7 seater
2010 Discovery D4 3.0l 7 seater.
20th Sep 2020 7:33 pm
dgardel
Member Since: 03 Nov 2009
Location: Greater Venice
Posts: 2025
I never used the Nanocom for the suspensions calibration. I'm skilled on IIDTool
Member Since: 03 Nov 2017
Location: Bristol
Posts: 9
Thanks. Not sure about getting access to an iiD Tool - would probably have to buy one. Unfortunately the links you provided don't work for me. Says "internal server error contact the system administrator". Any chance you could PM them to me? I'm desperate for information and to identify any potential solutions. thanks.1967 Series-2 2.0l petrol
1984 Range Rover Vogue 3.5 V8
1993 Discovery 1 200 7 seater
1998 Discovery 300
2003 Discovery D2 TD5 7 seater
2010 Discovery D4 3.0l 7 seater.
20th Sep 2020 8:11 pm
dgardel
Member Since: 03 Nov 2009
Location: Greater Venice
Posts: 2025
Member Since: 03 Nov 2017
Location: Bristol
Posts: 9
Many thanks. I'll check it out and get back with progress.1967 Series-2 2.0l petrol
1984 Range Rover Vogue 3.5 V8
1993 Discovery 1 200 7 seater
1998 Discovery 300
2003 Discovery D2 TD5 7 seater
2010 Discovery D4 3.0l 7 seater.
20th Sep 2020 9:58 pm
Boede
Member Since: 03 Nov 2017
Location: Bristol
Posts: 9
So, took car to independent Landy garage that has the LR SSD tool. This system reported a calibration failure due to the LR height sensor - solution is to replace it but I'm not convinced as both height sensors have been replaced with LR original parts. So still no further forward. Since then I replaced the cross articulation valve just to eliminate it - didn't make any difference. Still unable to level the rear of the car. There is only just enough s/w adjustment to get the LR ride height to 485mm (centre of wheel to underside of wheel arch) in "Normal" mode which then puts the RR ride height to 510mm and no s/w adjustment left to bring it down. So now thoroughly confused and frustrated. Would appreciate it if anyone feels like throwing in any other ideas at the problem. Returning to the Indy garage tomorrow for them to fit a new LR height sensor but don't believe that this will cure the problem.1967 Series-2 2.0l petrol
1984 Range Rover Vogue 3.5 V8
1993 Discovery 1 200 7 seater
1998 Discovery 300
2003 Discovery D2 TD5 7 seater
2010 Discovery D4 3.0l 7 seater.
29th Sep 2020 12:13 pm
Boede
Member Since: 03 Nov 2017
Location: Bristol
Posts: 9
Problem now solved . Went back to the independent Landy garage yesterday. They swapped the two rear height sensors from left to right and vice-versa. The fault remained on the left side - so sensor not a problem which stacks up as they are both new genuine LR parts. They then disconnected both L&R link rods from the top suspension arms and had one person on each to hold the sensor arms in an approximate normal position and a third person working the SSD calibration programme to perform a manual adjustment to set the ride levels somewhere about right to fool the calibration programme. The link rods were then replaced and the automatic calibration programme was activated which proceeded to calibrate the ride heights quite happily and set the vehicle to the exact ride heights. Car has been driven over the A-road with no return of the 30mph warning or dropping of the rear suspension so job done .1967 Series-2 2.0l petrol
1984 Range Rover Vogue 3.5 V8
1993 Discovery 1 200 7 seater
1998 Discovery 300
2003 Discovery D2 TD5 7 seater
2010 Discovery D4 3.0l 7 seater.
1st Oct 2020 9:40 pm
dgardel
Member Since: 03 Nov 2009
Location: Greater Venice
Posts: 2025
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
. Went back to the independent Landy garage yesterday. They swapped the two rear height sensors from left to right and vice-versa. The fault remained on the left side - so sensor not a problem which stacks up as they are both new genuine LR parts. They then disconnected both L&R link rods from the top suspension arms and had one person on each to hold the sensor arms in an approximate normal position and a third person working the SSD calibration programme to perform a manual adjustment to set the ride levels somewhere about right to fool the calibration programme. The link rods were then replaced and the automatic calibration programme was activated which proceeded to calibrate the ride heights quite happily and set the vehicle to the exact ride heights. Car has been driven over the A-road with no return of the 30mph warning or dropping of the rear suspension so job done 
