Is there any correlation between wrong air pressure in the tires and the ABS TC HD warnings?

The Disco is supposed to have 30 lbs in front and 46 lbs in the rear. That's beyond the understanding of the average service guy, apparently, so almost every time I take it in for an oil change or tire rotation I'll notice the warnings come on within a hundred miles or so of the service. I then immediately check the tire pressure and find that it's way off because the service people must have "corrected it" when they thought it was wrong. I had an oil change a couple of days ago and last night the amigos came on. Sure enough, the tire pressure was 36 in the front and about 39 in the rear. I actually saw the guy checking tire pressure and so I told him "it's supposed to be 30 in front and 46 in rear in case you were wondering", and he just looked at me and nodded, so I assumed he understood. He probably thought I was an idiot and changed the pressure anyway.

Anyway, I don't recall seeing any posts relating tire pressure and the amigos, but that's mostly the only time I ever see the amigos. When my tire pressure is correct, they never come on. Just a coincidence or is there possibly something to this?

 

Do an experiment, change the tire psi yourself and see what happens.
Put all four at 40, see what happens. Put all four at 30, see what happens. Each time you change the psi and the lights come on put the psi back to spec and see if the lights go back off.

 

When that happens it's just until the next start. The lights never stay on permanently. When the pressure is way off thenthe lights will come on about every 4th or 5th trip on average. You could say I've already experimented in this way: I first noticed there may be a correlation after having my tires rotated before the fishing trip you see in my picture. The tires were filled wrong on that trip 40 in front and 56 in the rear, and over the 8 hour drive out to the NC Outer Banks, the lights came on 3 different times, but when I aired down the tires for driving on sand I noticed that the pressure was wrong. Once on the sand the lights stayed off. They didn't come on for the rest of the trip, but they were at the correct pressure thereafter, except when driving on the sand where I had them all at 25 lbs. I assume that the soft sand being more forgiving than pavement had some mitigating effect. I aired them back up as soon as I hit the pavement again at a public air station. Once the pressure is corrected, then the lights stay off permanently. In case you're wondering, I'm not checking or clearing codes.Anyway, ever since then I've just known to check the air pressure as soon as I see the lights, and that usually just happens to be after a service, and the pressure happens to have been wrong every time.

 

I think what you're experiencing is called coincidence. More than likely you may have a sensor wire that's catching when the suspension is fully extended up on the lift, or one with a short in it. I'd get the codes read next time and see what you're dealing with. On another note, running 46psi in your rear tires is really only needed if you're towing or hauling large load. Otherwise it's giving you a rougher ride. I run about 30psi in the front and 36-38 in the rear.

 

jdelp, you may be right... but it doesn't happen enough to even be considered a minor inconvenience so I'll not be paying anybody to read codes just yet. I'm talking about 4 or 5 thousand miles between amigos on average. I agree with you that it doesn't make sense that air pressure would trigger the amigos, but it's an amazing coincidence.

 

Are you using stock tires or larger? When I got my Disco 1 the guy said that when he put larger tireson, the ABS light came on so he unplugged it. So does tire size not have any effect on the ABS light? Do you think the guy I talked tois full of IT? Should I plug it back in? Hope my info helped.

 

Tire air pressure has nothing to do with the Amigos.
I have driven 50 plu miles with as little as 18#s of air all the way around with no lights. On the other hand, I have run up near 60#s all the way around when hauling very heavy loads.
When the trio comes on it is ABS driven, usually sensor and will only be found if you can have the codes read while the lights are on.
Also, Discos run with more air pressure in the rear tires because of their weight distribution, the weight at the rear axlews is about 800#s higher then at the front axles.

 

As a tire deflates it becomes smaller and rotates more rapidly and vice versa.....since the ABS ECM is designed to look for sudden changes in tire rotation, it is possible that changes in the "spec" can trigger an ABS warning. Obviously, I can't say whether a difference of 8-10 PSI is enough to trigger a problem with the ABS ECM. My 2 cents but I too have seen a correlation w/my 2003 disco.

 

On the 04 with standard 18 inch, I run 38 PSI all around with no issues.

 

Sorry to help breathe life in this two year dead thread, but I thought I noticed a correlation between air pressure and the 3 amigos on my 03 too, but once I got a code reader, the only codes I ever get are for the shuttle valve switch. I think this is just a coincidence. Also, as has been pointed out earlier, the 46 psi for the rear tires is just for a truck loaded at maximum gross vehicle weight. The owners manual actually states under normal driving it should be 30 front and 38 rear.