Hi PiGo,
When my Plus Four warning light came on I filled up within 10 miles but could only get 26l in the tank. And that was filling slowly, stopping and starting the fill again, just to test how much I could get in. The manual gives a tank capacity for my car of 43 litres.
Based on that I had around 17l left in the tank when the the light illuminated. Interesting contrast to the manual which says that the warning light illuminates when 6l remains in the tank! The calibration/setting is obviously way out and I'll get the dealer to have a look at it along with a couple of other issues when we are out of lockdown.
Yes, tank capacity is 43l according to my manual.
Personally I wouldn't worry too much about the misfire and entering limp home mode as that is very unlikely to be the pump. Depending on the misfire detection system used in the B48 engine (probably crankshaft torque sensing rather than a spark ionisation system) the car's OBD system will shift to a reduced power mode to protect the catalyst from damage when it detects a certain number of misfires. This misfire could be down to a lack of spark or a lack of fuel but the detection is by torque only so the outcome is the same.
If the MIL was not on after refilling and power reverted to normal I think all is well. The error code in the ECU will be deleted after a certain number of misfire free engine running cycles.
