The P0135 error code in a Honda Jazz (also known as the Honda Fit in some regions) typically indicates a problem with the upstream oxygen sensor, also known as the air/fuel ratio sensor or O2 sensor. This sensor plays a crucial role in monitoring the oxygen levels in the exhaust gases, helping the engine control module (ECM) adjust the air-fuel mixture for optimal combustion.
Here are some steps you can take to diagnose and address the P0135 code:
1. **Inspect the Oxygen Sensor:** Check the wiring, connectors, and the sensor itself for any damage, corrosion, or loose connections.
2. **Check for Exhaust Leaks:** Examine the exhaust system for any leaks or holes that may allow air to enter and affect the sensor's readings.
3. **Replace the Oxygen Sensor:** If the sensor is old or damaged, it may need replacement. Consult your vehicle's service manual for the correct sensor part number and replacement procedure.
4. **Clear the Error Code:** After making any necessary repairs or replacements, use an OBD-II scanner to clear the error code and reset the ECM. This will turn off the Check Engine Light.
5. **Monitor for Recurrence:** Drive the vehicle for a while and see if the P0135 code returns. If it does not return, the issue has likely been resolved. If it does come back, there may be a more complex problem that requires further diagnosis.
If you're unsure about any of these steps or lack the necessary tools and experience, it's recommended to have a qualified mechanic or Honda dealership technician inspect and repair the issue, as they will have the expertise and equipment to diagnose and fix the problem accurately.