After a repair: how to be sure it is actually fixed
An empty fault list at the garage means nothing. What to check before you pay.
Save the state BEFORE the repair
The pre-repair report is the only thing you can compare against later. It holds the codes, the freeze frame and the readings. Without it the conversation comes down to «feels a bit better», which is an argument for no one.
Do not accept the work on an empty fault list
After a repair the codes are always cleared — that is part of the job. An empty list right after the reset proves nothing: the unit has not tested itself yet. What matters is readiness, and it builds up over a drive, not over a minute on the lift.
Check the same reading that was wrong
If the oxygen sensor was replaced, watch how it swings now. If a leak was chased, watch the trims: they must return to zero, not merely «get smaller». The number before and the number after — that is the acceptance.
Drive the mode where the fault actually lived
The freeze frame says at what revs, load and temperature the fault was recorded. Repeat exactly that: a cold fault is not tested on a warm car, and a fault under load is not tested standing outside the garage.
Give it a few days
Some faults do not come back at once: the unit needs several drives with warm-ups to finish its checks. If the code returns after three days, that is the same repair, not a new fault — the conversation with the mechanic continues rather than starts over.