Hello!
I'm new to the forum, but I've been "lurking" for a few months and I have a few questions. My son owns a 2005 LR3 SE7 4.4L with @ 172,000 miles on it. He purchased it this past summer....actually he traded someone for it. This local fella owned it and was commuting to Pittsburgh PA every week from New Hampshire to visit his family. The cost of fuel for him was way too much, so he put an add out asking if anyone with a Prius was willing to trade for it. My son happened to own a Prius, so they worked out an even swap. Anyway...the LR was well maintained (so was the Prius) and has been an enjoyable vehicle so far. The only real issue is with the various drive "modes". The vehicle has a "Special Programs Off" message on the dash when you try to select one of the various modes on the console. Hi and Lo gears in the transfer case work fine, just the rotary mode switch does not engage any mode other than I guess "normal driving". I scanned the vehicle for codes with my AUTEL scanner and it shows the following DTC's:
U0416-94 Invalid data from vehicle dynamics control module
C1A98-01, C1A98-86 & C1A97-86 YAW Sensor Circuit & Lateral Accelerometer Circuit
U0122-87, U0416-94 Lost Communications with vehicle Dynamics Control Module

The previous owner also had removed the air ride system and replaced the air shocks with conventional springs.
Can anyone here offer any advice on what to look for to fix the "mode" issue? Might it be caused by the removal of the air ride stuff?

Thanks in advance!

 

I dont think the conversion is causing issues, no codes relate to that. Sounds like your yaw sensor is potentially bad. If so this is only the second time I heard of that issue and it was recently on here. If you have a GAP tool, I think you can load the value live. With the other forum member, it fluctuated even though the vehicle was not moving. A used replacement sensor fixed it. The Lateral Accelerometer Circuit would be similar I would guess. I would get a live value and see what comes up. Odd that both those particular sensors would be an issue. The only other scenario I can think of off hand - and I am totally guessing here - is the share a common ground or wire loom that fed the air suspension module and that wiring was either cut or unplugged.

DISCO3.CO.UK - View topic - Lateral Accelerometer Reading

Edited to add: Those lost communication faults are typically ghost faults, meaning they just come up from time to time for no real reason. If you clear then and they done come back right away, you can ignore.

 

Took this pic of my scanner while driving the vehicle. Yaw sender value never changed. I had my son swerve the car back and forth while moving to see if the yaw value would change but it never did. Question-would the tires have to break traction for yaw to activate?

 

Thanks for your input! I will check the yaw sensor

 

Yaw will activate if in park and you sway the vehicle. Its literally just a g-force type sensor. So nothing has to happen for it to work, it just always does.

 

Great info! I think that would confirm the sensor is not working…gonna order one asap and I will report back after I install it. Thanks again!!✌️👍

 

So my son purchased a Yaw sensor I think from Rovers North. We installed it and it still seems to not be working. The value is still stuck at -100 on my scanner. The “new” sensor is a Bosch unit, same as what was in the car. Does anyone know how to test these things out of the vehicle? The “new” sensor did not look very new by the way. I think it may have been a take off from another vehicle.

 

Is the engine running when you check the value? I am pretty sure the default value should be zero as a value of 0.2g is enough to disable the EAS when in motion.. I dont see anything in the shop manual saying it needs calibration, but poke around GAP and check. Also did you check the wiring integrity?

edit: Sorry, keep forgetting you dont have a GAP tool. I wonder if that is the actual issue since yaw is measured in g-force, not degrees as your tool says.

 

I did check the value while the vehicle is in motion. You may be right about my scanner not being able to read what’s going on. Any other hints as to what to look for when troubleshooting the terrain mode not working?

 

Are you getting the same codes? FYI, the LR3 does not use a lateral accelerometer except for the SRS system. I dont think those sensor feed into anything else at all. I wonder if your tool can not read some of the Rover specific codes? Does that tool requires you to pick a vehicle first? Should be the L319. Because if the yaw sensor is not an issue - still can not say for sure - then really there should be more codes.