Jumper Automatic Transmission Problems

I had similar problems with my Citroen Jumper. Transmission performance was awful, the automatic gearbox was slipping, and it turned out to be related to undervoltage causing issues with the hydraulic fluid. Have you checked your battery and charging system lately? Maybe get a diagnostic check.

Thanks for the suggestion! I hadn't considered undervoltage. Is there a specific test I can do to check the battery and charging system myself, or is it better to take it to a workshop?

While you could check the voltage with a multimeter, I'd recommend taking it to a workshop. They can properly load-test the battery and alternator. In my case, the undervoltage damaged the transmission control unit. The workshop confirmed the issue and after replacing some parts the problem disappeared. It is better to prevent further damage by visiting a professional.

Okay, I understand. I appreciate your advice! I'll take it to a workshop to get it checked out. The repair cost 240€ for me. Now the automatic transmission shifts as usual. Thanks again for the help diagnosing the problem.