Renault Master Transmission Issues

Sounds frustrating! I had a similar issue with my old Volvo V70. Different car, I know, but the symptoms sound eerily familiar. My problem turned out to be a dodgy connection to the transmission pressure sensor. Basically, the computer wasn't getting the right signals from the sensor because of a corroded or loose plug. It caused all sorts of weird shifting problems. Have you checked the wiring and connectors going to the pressure sensor? A bad connection could definitely trigger those lights and put the transmission into limp mode. It's worth a look before you start replacing expensive parts. A pressure sensor is usually located on the radiator, so check the plug connection there.

Thanks for the tip! I'll definitely check the connections. When you say 'connection to the transmission pressure sensor', do you mean where the cable plugs into the sensor itself, or somewhere else along the wiring? Is the pressure sensor on the radiator?

Yep, exactly that - where the cable plugs directly into the sensor. Give it a wiggle and see if anything changes. Also, trace the wiring as far as you can easily see, looking for any obvious damage or chafing. In my case, the corrosion was actually inside the plug itself, so it wasn't immediately obvious. I just cleaned everything up with some electrical contact cleaner and it sorted the issue. You are right, the pressure sensor should be on the radiator itself. But if that doesn't solve it, I'd recommend getting it to a workshop. Messing with transmissions can be tricky!

Thanks so much for the advice! I checked the cable and plug connection of the component and you were spot on – it was a corroded connection! Cleaned it up, and everything seems to be working fine now. Cost me 95€ at the workshop. Really appreciate you sharing your experience!