Federal With A/T

Notice: This article has been updated with TSB# 99-T-66A, dated Sept. 2000.

DTC P0133 - 02S #1 SLOW RESPONSE

Wiring Diagram:

After achieving closed loop fuel control, a commanded air fuel ratio of 14.7:1, RPM between 1500 and 3200 and air flow between 7 and 25 grams per second the PCM will continuously monitor the front oxygen sensor signal for 100 seconds. During this time the PCM counts the number of rich to lean and lean to rich switches. To be considered a switch the voltage must go below 300 mv and above 600 mv. The PCM also keeps track of the time it takes to make the switch. The number of switches along with the time to achieve these switches are used to calculate the average response time to perform each switch. Also this information is used to calculate if the proper ratio of the switches is correct. The three diagnostic trouble codes listed below are used to identify different types of faults that can occur with oxygen sensors.

DTC PARAMETERS
This DTC is set if the average response time of the switches from the sensor is too slow after the 100 second test is performed. If the LEAN TO RICH time is greater than 125 ms or the RICH TO LEAN time is greater than 156 ms this code will set.

DIAGNOSTIC AIDS

REPAIR PROCEDURE
1. The oxygen sensor wiring and connections should be checked if any of these DTCs are set because corrosion or loose connections could cause these DTCs to set.
2. The most likely cause of setting any of these DTCs is contamination. This contamination could be caused by fuel, improper use of RTV sealant, engine oil, or coolant contamination.
3. The source of contamination should be identified and corrected before replacing the sensor.


TSB 99-T-66A

MODELS AFFECTED:



1999 Saturn S-Series vehicles equipped with DOHC (LLO) engines, automatic transaxies (MP7) and federal emissions (NF2)


CONDITION:
The affected vehicles may exhibit a SERVICE ENGINE SOON telltale On and a DTC P0133 - 02S SLOW RESPONSE, SENSOR 1.

CAUSE:
The response times (Lean-to-Rich and/or Rich-to-Lean) of a normally operating oxygen sensor may exceed the values set within the current PCM calibration.

CORRECTION:

DTC P0133 Correction: