What must be done prior to running a TSI Smog inspection?

• A. All accessories must be turned off, and the vehicle must run for at least 30 seconds in park or neutral.
• B. The vehicle must be in drive and run for at least 60 seconds.
• C. Test must start immediately after starting the engine with the hood closed.
• D. Only the ignition system must be on; run for 15 seconds.

Answer: (A)

Before a TSI Smog inspection, the engine needs a short warm-up with no electrical load so the readings are stable and accurate. With the car in Park or Neutral and the parking brake set, run the engine for at least 30 seconds with all accessories off (no A/C, radio, lights, etc.). This lets the engine reach proper operating temperature and lets the exhaust and sensor readings settle to normal conditions. If you skip this and start the test right away or have accessories on, the readings can be off because the engine isn’t stabilized yet. Being in Drive or trying to test while the engine is still cold or under load would also skew results, which is why Park/Neutral with a 30-second idle is required.