From Diagnosis to Parts Verdict
The parts recommendation belongs after the failed component has been proven. This page closes the loop without turning a code into a shopping list.
1. Prove the failed system
Finish the diagnostic branch until the evidence isolates the component, circuit or mechanical fault. “Common failure” and “code present” are not proof.
2. Confirm application
Match year, engine, transmission, ABS/TCS, rear axle, brake package and installed modifications before choosing a replacement.
3. Open the Parts Verdict
Only after the failure is proven should OEM-required, aftermarket-with-caveat or aftermarket-OK guidance influence the purchase.
4. Verify the repair
Re-run the exact failed test, clear/complete the applicable monitor if needed, road-test in the original complaint state and inspect for collateral issues.
Modified-car rule
Compatibility is part of the repair. A “better” part can still create a new problem if the tune, wiring, driveline, brakes, ABS/TCS or geometry no longer match.
DO NOT BUY YET
If the diagnostic still has two plausible branches, the part has not been proven yet.