Whos mentioning codes?
A real shop doesnt play with codes or battery disconnects or 200 kph runs.
A real shop looks at the primary and secondary valvebody regulating pressures to see if something is not upto par (slower buildup) etc or excessive temperature spike to âsee anything abnormalâ - further diving can be done by direct probing to see if reports arent lying. (Happens a lot)
Just like shops can ascertain the life of an older unit by checking the fill times and shift handover duration on older autos
All of such data is available in the control unit PIDs (active data) with help of a deeper level scan tool.
Lol, codes!!! , its not 1989 anymore.