Circuit Description
The oxygen sensor 1 (02S-1) is an electrical source that responds to
oxygen content in the exhaust manifold. When the sensor reaches approximately 316°C
(600°F), it produces a voltage based on the difference in oxygen between the atmosphere
and exhaust gas. The PCM sends a bias voltage (399-499 mV) on the signal
line, which is pulled up through high resistance. When the O2S-1 is cold, it produces
no voltage and has extremely high internal resistance. The internal resistance of
the sensor is much greater than the resistance of the bias pull-up resistor. However,
when the sensor heats up, it produces voltage that overrides the bias voltage. This
voltage is read by the PCM to determine a rich/lean O2S-1 signal used to adjust injector
pulse width. Under normal conditions, low sensor voltage means high oxygen content/lean
air-fuel mixture and vice versa. Normal sensor readings will fluctuate between 10 mV
and 1065 mV. DTC P1133 sets when the O2S-1 signal has too few switches
(under 300 mV to over 600 mV and vice versa) over a certain length of
time.
Conditions for Setting the DTC
DTC P1133 will set if the O2S-1 rich/lean transitions are less than 1
(auto) / 2 (manual) or lean/rich transitions are less than 1 count when:
| • | Engine run time is greater than 3 minutes and 20 seconds |
| • | Engine speed is between 1800 and 2300 RPM (auto), 2350 and 3000 RPM
(manual) |
| • | TP angle is between 8 and 15% (auto) / 22 and 40% (manual) |
| • | ECT is greater than 75° (167°F) |
| • | Fuel level is greater than 10% |
| • | EVAP purge solenoid DC is greater than 80% |
| • | No CKP, ECT, EVAP, fuel injector, fuel tank pressure, fuel trim, IAT,
idle speed, MAP, misfire, PCM internal fault, or TP sensor DTCs have been set. |
DTC P1133 diagnostic runs once per ignition cycle for a maximum of 30 seconds
once the above conditions have been met
P1133 is a (type B) DTC
Diagnostic Aids
Possible causes of DTC P1133:
| • | An intermittent connection or corrosion in the O2S-1 harness connector
can set this DTC. Use Scan tool to monitor O2S-1 voltage with engine running at normal
operating temperature while wiggling the signal and ground wire. Make sure the sensor
is tight. |
| • | The most probable cause for DTC P1133 is contamination. Check for
obvious contamination (oil, fuel or engine coolant) by removing sensor. Identify and
correct the cause of the contamination if contaminated. Replace the O2S-1. |
