G'day coxo, I've got the same error in my 2015 Ducato 3.0 litre Multijet 180 with Comfortmatic. My error message is showing as blue coloured and "Intermittent", where I believe this is occuring because the Hydraulic Pump is occasionally failing to come on and bring the pressure up. Tell us, do you hear the very low volume buzzing sound of the Hydraulic Pump priming up to pressure when you approach the vehicle and open the driver door? You have to listen very carefully. If you miss it, you may still hear it again when turning the ignition key on. If the pressure is below around 33 bar, it'll run the pump and prime back up to around 46 bar where it stops.
You can also use
MultiECUScan to check the Parameters from the Transmission Control Unit, where it will list such things as: "Hydraulic Circuit Pressure" and "Pump relay control". Monitoring these paratmeters you can see when the pump switches on and off and at the same time, watch the pressure build up, then slowly drops again. I just sit in the driver seat for some minutes with the ignition on and no engine running, monitoring parameters. The Hydraulic Pump cycles on after a while, as the built up pressure will drain through a "return line" leading back to the Hydraulic Reservoir which you've just topped up.
I'm not absolutely certain, however I'm led to believe the "Max" fluid level mark on the Hydraulic Reservoir is the "join line" where the two halves tank bottom and tank top join together see image below - please correct me if I'm wrong. I've been unable to detect any other "Max" level marker and this joint line was mentioned over on another forum. I mention this, as it's quite alarming how far down from the top of the filler, that level is and that's where I found mine when I first looked. Nonetheless, if you've over filled it, I'm also led to understand the excess will eventually drain out of the overflow tube as the system levels itself during use.
Hopefully someone on here can confirm that is the level marker in the image below. Please correct me if I'm wrong and I'll fix the image.
PS. Thanks for the photo MSjoberg showing hydraulic pump relay and fuse, including their numbers. Much appreciated.
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