Jaguar Repair Problems? Ask a Jaguar Repairs Expert.
Is that the only code present?
OK P0778 is for the 2/4 brake pressure control solenoid. Lets go right to the large rectangular connector at the transmission to make sure it is clean and secure. We can test it with a digital multimeter.
You can check the resistance of all the solenoids right at the large rectangular connector on the transmission. Ohm pins 13 and 18 and it should read near 14-18 ohms and pins 16 and 18 and that should read about 2.6-3.2 ohms. If the resistance values are within range then we need to check for water leaking into the TCM. The TCM is located behind the driver side dash. Look behind the fuse box and you will see a small gray box. This is the auto wiper module. Remove the 10mm nut and that module/bracket will come out. Then remove the two 10mm nuts off the TCM then pull it out and disconnect it. Look at the harness connector and module for signs of water.
Ok either the wire is broken inside the transmission or the solenoid is bad.
Ok we definitely need to make sure the fluid is full but we are going to lose fluid if the solenoid is replaced.
The front pan will need to be removed then the fluid level rechecked.
Just checking in to see if you need any further assistance. Your question is still open on my end since it has not been rated yet. Let me know if you need anything else.