When the catalog and the car disagree
Somebody fitted the wrong part before you
One straightforward possibility is a previous repair that used what was available rather than what was specified. The car may have been carrying that part since.
The fasteners around it can provide clues. A correctly fitted part uses the specified hardware; improvised fixings can suggest a substitute, but do not prove it on their own.
The part was superseded and looks different
Supersessions are not always cosmetic. A replacement design can change shape, connector type or mounting while remaining the correct current part. What is on the car may be the old design, correctly fitted, years ago.
The chain will show it. See what a parts supersession is.
The car was built across a running change
Manufacturers change specification mid-production without announcing it, and cars built either side of the change take different parts under the same model year. The catalog usually notes a build date or VIN break.
If the entry shows two options with a date condition, check the car’s build date rather than its model year. Our post on model year versus production date covers the difference.
The car is not what the paperwork says
Imported and re-registered cars sometimes carry paperwork describing an equivalent local model rather than the actual factory build. Compare the physical VIN with the supported manufacturer record and the registration document.
If they disagree, verify the vehicle’s identifiers and resolve the discrepancy; do not choose whichever source makes the order easier.
You are in the wrong market build
A catalog opened without a VIN, or with the wrong market pre-selected, can show a plausible but incorrect answer. This failure can be difficult to notice.
Repeat the supported VIN lookup and check the returned vehicle and market before drawing a conclusion.
The car has been modified
Retrofitted equipment, converted bodies and aftermarket upgrades all leave a car that no longer matches its build record. The catalog is still right about what the factory fitted.
At that point you are working from the part on the car rather than the record, which is a different job and worth pricing as one.
Frequently asked questions
The catalog shows a different part to the one fitted. Is the catalog wrong?
It can be, but first check: a previous incorrect repair, a supersession, a running change, incorrect paperwork, the wrong market build or a modification. Verify any unresolved catalog record.
How do I check for a running change?
Look for a build-date or VIN-break condition on the catalog entry, then compare it with the car’s build date rather than its model year.
What if the registration document contradicts the VIN?
Compare the physical VIN with the supported manufacturer record and verify any discrepancy. Imported or re-registered cars can have paperwork describing an equivalent local model.