In this guide, you will learn how to use the YOUCANIC scanner to:

  1. Read Engine Control Unit Fault Codes
  2. Clear Engine Control Unit Fault Codes
  3. Check if Vehicle is Ready to Pass Smog/Emission

If you don’t have a YOUCANIC UCAN-I scanner, you can purchase one on Amazon and get it delivered to you in the next ONE or TWO days.

For those looking to diagnose all vehicle systems, including ABS, Airbag SRS, Transmission, or any control unit in the vehicle, the YOUCANIC full system scanner is required.

1. Read Fault Codes

  1. Locate the diagnostic port under the dashboard.
  2. Plug the scanner into the port.
  3. Turn on the ignition but do not start the engine. If the vehicle is equipped with a START/STOP button, press it once or twice without pressing the brake pedal.
  4. The scanner turns on automatically. Press enter.
  5. Select Diagnostic then press Enter again.
  6. Go to Read Codes.
  7. Press enter.
  8. Fault codes will be displayed on the menu. Press the down arrow in case more than one code is present.
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Check both Stored and Permanent codes.

  • Stored codes – Confirmed issue by the engine control unit. These codes are why your check engine light (CEL) is on.
  • Pending codes – Issues in the engine control unit have been detected but have not confirmed yet. These codes will trigger CEL when confirmed. The CEL will check for these codes several times before it changes the code from Pending to Stored and triggers the CEL ON. Until codes are confirmed, you will have pending codes and the CEL off with no stored codes.

2. Clear Fault Codes

003033601 (1)

  1. Reconnect the scanner to the diagnostic port.
  2. Turn on the ignition.
  3. On the main menu, go to Clear Codes.
  4. Press enter to clear the fault codes.
Fault codes may not clear and the check engine light will not reset if the problem was not fixed.

3. Check if the vehicle will pass the Emission / Smog Test

This procedure will show you if your vehicle passes smog test. You don’t need to drive to the test station to determine whether the vehicle will pass.

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  1. Connect to the OBD-II port.
  2. Turn on the ignition but do not start the engine.
  3. Select Diagnostic, then press enter.
  4. Scroll down to I/M Readiness, then press enter.
  5. The next screen will show systems that have been tested.
For the car to pass the emission test MIL* should be OFF; all systems should say OK or N/A. If you have incomplete (INC) systems vehicle will not pass the smog test. MIL stands for Malfunction Indicator Light. It is another acronym for Check Engine Light (CEL).


  1. Works on ALL OBD II Enabled vehicles, both Gasoline and Diesel-oil cars – domestic and imported.
  2. Features the unique patented One-Click Readiness Key for quick State Emissions readiness check and drive cycle verification.
  3. Built-in speakers provide both visual and audible tone for readiness verification.
  4. Retrieves generic (P0, P2, P3, and U0), manufacturer-specific (P1, P3, and U1) codes, and pending codes.
  5. Quickly determines the cause of the Check Engine Light(MIL)
  6. Turns off Check Engine Light (MIL), clears codes,  and resets monitors
  7. Views freeze frame data  OBD2 / EOBD / CAN Car Diagnostic Scanner supports all 10 OBDII test modes on all OBDII compliant vehicles for a complete diagnosis. The UCAN-I is truly the ultimate in power and affordability, allowing users to do their jobs faster.
  8. Displays monitor and I/M readiness status (emissions)
  9. Reads live PCM datastream
  10. Shows live O2 sensor test data
  11. EVAP System test data.

Vehicle Coverage

This scanner will work on all OBD-II compliant vehicles. Here is a quick reference so

North America Vehicle Market

  • All vehicles sold in the US since 1996 are OBD-II compliant. That includes Dodge, GM, Chevrolet, Ford, BMW, Audi, Mercedes-Benz, Mitsubishi, Honda, Toyota, Kia, Hyundai. If the vehicle was sold in the US, it had to have OBD-II, which means this scanner will be able to read and clear codes.

Vehicle manufacturers did not install OBD-II equipment on all vehicles if the vehicle was sold in a different market. If you live in Europe or Japan, the OBD-II wasn’t available until 2003 and 2007, respectively.

European Vehicle Market

  • All vehicles 2003 to present made by Alfa Romeo, SAAB, Acura, Opel, Audi, Seat, Bentley, Skoda , Daewoo, Benz , Daihatsu, Land Rover, BMW, Vauxhall, Volvo, VW, Ford, Jaguar etc.

France Vehicle Market

  • All vehicles 2006 to present including Citroen, Fiat, Peugeot.

Japanese Vehicle Market

  • All vehicles 2007 to present. Including KIA, Isuzu, Honda, Mitsubishi, Hyundai, Dacia, Lexus, Mazda, Nissan, Subaru, Suzuki, Toyota.

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