Hella TPMS

[surfgeek33]

Hello all!

Just picked up our SMB last week and having a blast with it. Unfortunately, we also could not figure out our Hella TPMS that SMB West installed. This is our first 4x4 vehicle and we are new the world of checking your tire pressure frequently, airing down, etc.
The issue we're having is that the tire pressure from the TPMS does not match the pressure when I take a manual tire pressure. We have a reliable, hand held, tire pressure gauge. Every time I check all 4 tire pressures (manually) and I come back inside the rig, the Hella is giving me a different reading. Any suggestions? Thanks a Bunch.

-Ray

[Ed in Montana]

Surfgeek, when I check my tire pressure using a good hand held tire pressure gauge, my inflation pressures are usually 2- 3 lbs greater than those measured by the Hella system. I am guessing this would be within the margin of error for any pressure gauge.

As for getting the two measuring devices to agree, I don't have a clue. As long as the measuring errors are consistent, I am not going to worry much about it.

[yvrr]

Since my last post, I had the tires rotated on our van and thus had to reprogram our Hella TM System. While doing that, I played with the antenna and discovered that if the antenna was parallel to the centerline of the van, it wouldn't receive signals at all from the tire sensors (which I've been calling transmitters). So I stretched the antenna out and duct taped it to the firewall under the steering wheel and that seemed to work....on a subsequent trip to the Sierras, I lost the signal only twice, once on the way up and once on the way back. (I would not call that success though.) However, this time, I lost the signal from the left rear tire (before, it was always the right rear tire). This was not due to the original sensors since the tires were rotated front to back and back to front, not side to side.

(To check signal strength, disconnect the wires from the battery to the receiver. This will cause the unit to lose its stored memory and require that you go through the entire setup procedure again. But that gets you to the first step in which the receiver checks signal strength and displays it.)

I received a complete replacement package from Hella last week with replacement sensors, receiver module, etc. I decided that the best mounting location would be near the centerline of the van. I pulled the engine cover and found that I could mount the replacement receiver just to the driver's side of the AM/FM radio. There is a steel plate there and I made a mount using a piece of 1/8" acrylic which was drilled and tapped for screws to mount the receiver. I used pop rivets to attach the acrylic to the steel plate and then mounted the receiver. The antenna was extended out toward the center of the van under the radio. That puts the antenna right at the center of the van. I checked the signal strength at this location and it was optimal (3 bars). I didn't bother replacing the wheel sensors since I don't think that they are part of the problem.

We've only taken a short (150 mile total) trip with the replacement receiver and had no failures. We are planning a 10-day trip right after Labor Day and, hopefully, the replacement receiver and new location will solve our problems.

Our original receiver has been shipped back to Hella who will do a bench test on it and install it in a vehicle for testing. Hopefully, they will report back to me on what they find. I'll let everyone know...