Need to go and get laptop plugged in I know but just incase some has had same fault.
For the first half hour or so in the morning gearbox will misbehave, I can select gear and pull away, it may change up a few cogs then just run out of drive. Worse if it appears to be ok and I press on only to discover it will not change down OR select neutral! just a bit interesting if lights are red. :shock:
I have been forced to stall it or key off a couple of times.
Past couple of days I have selected parking based on being able to get going and run for at least 20 mins, then all is ok.
Noticed that just before fault is about to appear, a slight drop in air pressure from 12 bar down to 10 or 11 and a tingling rattle.
If it were a Volvo FH I would say to change the large power relays 1-4, not sure if the magnum has the same setup?
We have seen similar faults with FH’s & changing the relays cures it.
As Wagger said, have had problems like this myself and usual cure has been to replace a relay.
Be sure to check that you replace like for like as they do have subtle differences.
Worst case scenario you get main agent to re-programme I-shift, shouldn’t cost more than £100.
Common fault on ZF/Mercedes autos.
The seal on the control finger box allows moisture to enter the control box.
As the box cools it â– â– â– â– â– air in and condensation forms in the housing shorting out the position detector nodes.when the box gets warm the moisture evaporates and the control unit works ok after about 20 minutes.
There is a modification to stop moisture ingress.New seal and plastic control box.
:shock: