Whats Cause this Code P1133
Staging Lane
Joined: Aug 2002
Posts: 53
Likes: 1
From: Florida
Re: Whats Cause this Code P1133 DTC P1133 Circuit Description
The PCM monitors the Heated Oxygen Sensor (HO2S) activity for 100 seconds. During this monitor period the PCM counts the number of times that the HO2S switches form rich to lean and lean to rich. A DTC P1133 sets when the PCM determines that the HO2S did not switch enough times.
A lean to rich switch is determined when the HO2S voltage changes from less than 300 mV to greater than 600 mV. A rich to lean switch is determined when the HO2S voltage changes from more than 600 mV to less than 300 mV.
Heated Oxygen Sensors Operation
The Heated Oxygen Sensors are mounted in the exhaust system where they can monitor the oxygen content of the exhaust gas stream. The oxygen present in the exhaust gas reacts with the sensor to produce a voltage output. This voltage should constantly fluctuate from approximately 100 mV (high oxygen content = lean mixture) to 900 mV (low oxygen content = rich mixture). The heated oxygen sensor voltage can be monitored with a scan tool. By monitoring the voltage output of the oxygen sensor, the PCM calculates the fuel pulse width command to give to the injectors (lean mixture/low HO2S voltage = rich command, rich mixture/high HO2S voltage = lean command).
The PCM monitors the Heated Oxygen Sensor (HO2S) activity for 100 seconds. During this monitor period the PCM counts the number of times that the HO2S switches form rich to lean and lean to rich. A DTC P1133 sets when the PCM determines that the HO2S did not switch enough times.
A lean to rich switch is determined when the HO2S voltage changes from less than 300 mV to greater than 600 mV. A rich to lean switch is determined when the HO2S voltage changes from more than 600 mV to less than 300 mV.
Heated Oxygen Sensors Operation
The Heated Oxygen Sensors are mounted in the exhaust system where they can monitor the oxygen content of the exhaust gas stream. The oxygen present in the exhaust gas reacts with the sensor to produce a voltage output. This voltage should constantly fluctuate from approximately 100 mV (high oxygen content = lean mixture) to 900 mV (low oxygen content = rich mixture). The heated oxygen sensor voltage can be monitored with a scan tool. By monitoring the voltage output of the oxygen sensor, the PCM calculates the fuel pulse width command to give to the injectors (lean mixture/low HO2S voltage = rich command, rich mixture/high HO2S voltage = lean command).
Re: Whats Cause this Code P1133 You check o2's at wot for performance & pcm watches o2 all the time in closed loop for fuel trim adjustments. You need to determain when o2 is having problems it's probably at idle. O2's have to be 600 degrees to operate correctly & when they get degraded & slow they need to stay hotter to remain active. This is assuming you don't have a running problem in this bank. All we know is pcm is seeing b1s1 o2 is not switching so it's either lean, mid biased, or rich when problem occurs. You need to catch it when it is and it should'nt be hard to fix from there. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
