Circuit Description

Powertrain Control Module (PCM) continuously monitors Oxygen Sensor 1 (O2S 1) activity for 100 seconds. During the monitor period, PCM counts number of times than O2S 1 switches from rich to lean and from lean to rich. If total number of switches is less than calibrated value, a DTC P1133 will set.

Conditions for setting this DTC are as follows:

• Number of lean to rich counts is less than 15 or rich to lean counts is less than 10.
• Engine speed is 1600-2600 RPM.
• TP sensor angle is 8-20 percent.
• No presence of Codes: P0106-P0108, P0112, P0113, P0117, P0118, P0121-P0123, P0300-P0304, P0506, P0507, P1441.
• Purge learn memory is greater than 191.
• Evaporative emission control system is commanded open for greater than 60 percent Pulse Width Modulated (PWM).