I had these
exact fault symptoms on a local members car today.
T4 connected, and complained about the EWS, bypassed that screen and got into the main diagnostic tree.
Progressing through the check, the car would not talk to the LSM, so it was removed to check, and indeed replaced temporarily as an aide by elimination only, which made no difference.
T4 would talk to the EWS with the LSM disconnected, and vice versa but not with both together.
While I was reassembling the car, and I have to say it was absolutely tipping down, I happened to glance into the rear footwell, which was full of water
Now the car itself was a very strange spec indeed, Classic fitted with manual double piped leather seats, so I took a look at the rear footwell, and covered over with a carrier bag was the wiring plug for electric seats, denoting this car has the highline loom fitted from factory sitting in a puddle under the seat, it's contacts all green and corroded !!!
After a quick clean of the plug with Isopropanol and a toothbrush while the owner made a cuppa, and normal service was resumed
So in answer to the question posed by the OP, yes T4 would help diagnose this type of problem, and yes it helps to know what might also cause this type of problem in the first instance
I've had these symptoms before on a Contemporary SE fitted with memory sports leather, where the K-Bus wiring to the memory seat module was damaged, so why not take a torch and have a look see?
Many moons back, but take a look
HERE
Brian
