RRAustria said:

Got a 2004 L322 TD6 and recently replaced the rear left height sensor (had air suspension inactive message and old height sensor turned out to have a broken arm). I replaced the sensor with an aftermarket one, cleared all faults (IIDtool) and recalibrated the sensor. Everything seemed fine but after a minute on the motorway (soon after the car lowers itself to motorway height) I get the air suspension inactive message again (no cluster lights but air suspension lock light is on). Error codes from IIDtool are: 81 - rear left height sensor activity invalid and 8A - air suspension can error. I can clear the codes and air suspension works for a few minutes but then same thing again. Sometimes the air suspension goes into hard fault mode (35mph max message) and I get "rear right height sensor error". Right side error only comes on if left side has shown activity invalid first.
Tried several things (locked suspension moves, changed motorway height to not lowering at all) but the air suspension inactive warning comes on in 99% when the motorway speed is reached for a minute or so.

What could this be? bad BCM? chafed wires? I'm really stumped.. should I go to a stealer and have them read the codes?

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mark and clare said:

I had nightmares with my P38's eas, diagnostics initially pointed at a duff height sensor, which was duly changed. trying to reset the heights proved impossible even with dealer kit and the help of an electronics 'expert'. to cut a very long story short- the new sensors come with a bit of loom that allows you to plug it in without removing the under wing guards, sounds real handy but, what had happened is that over time the connections in the original wiring had corroded and were sending a corrupted signal to the eas ecu. Take the time to remove the under wing guards and check out the existing connectors. I have over 250,000 miles on the clock now and perfect eas. Good luck!

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