Malfunction Indicator Lamp (MIL)/Service Engine Soon (SES) Lamp Illuminated, DTC P0133 (HO2S Slow Response Sensor 1) Set (Reprogram ECM, Check Date Code on Oxygen Sensor and Replace If Necessary)

Some customers may comment that the Check Engine or SES lamp is illuminated. Technicians may find DTC P0133 (HO2S Slow Response Sensor 1) set.

Technicians should inspect the front O2 sensors (and replace if necessary), then reprogram the ECM on all vehicles affected by this condition following the procedure below.

1. Remove the front O2 sensor. Refer to Heated Oxygen Sensor 1 Replacement (2.0L L34) in SI.



2. Inspect the front O2 sensor date code (1). The date code can be interpreted as follows:

•	1st digit = year (6 = 2006)

•	2nd digit = month (A = January, B = February, C = March, D = April, and so on)

•	3rd/4th digits = day of month

3. If the date code is 6D20 (April 20, 2006) or prior, replace the front O2 sensor with P/N 96418971. If the date code is after 6D20, the front O2 sensor does NOT need to be replaced.
4. Check the vehicle configuration (automatic or manual transaxle) to determine the correct calibration.

Important: Prior to reprogramming, check the battery voltage state. If the battery is not fully charged, charge the battery.

Important: Prior to reprogramming, make sure the Tech 2® is updated with the latest software.

5. Reprogram the ECM with the appropriate calibration (or later) listed below. These calibrations, or any that follow, are designed to address this concern. Refer to Service Programming System (SPS) in SI.

The new ECM calibrations will be available to dealerships in TIS2Web version 2.5 for 2007 (available 2/19/07). If you cannot access the calibration, call the Techline Customer Support Center (TCSC) at 1-800-828-6860 (English) or 1-800-503-3222 (French) and it will be provided. As always, make sure the Tech 2® is updated with the latest software version.

6. Check for any DTCs in the ECM/TCM. Clear any DTCs that are stored.

For vehicles repaired under warranty, use: