P0133
DTC P0133 HO2S CIRCUIT SLOW RESPONSE (BANK 1 / SENSOR 1)Component Location:
GENERAL DESCRIPTION
In order to control emissions of the CO, HC and NOx components of the exhaust gas, heated oxygen sensor (HO2S), mounted on the front side and rear side of catalytic converter, detects the oxygen content in the exhaust gas. The front HO2S signal is used to control air/fuel ratio (closed loop fuel control) and the rear HO2S signal is used to monitor front HO2S and catalyst for proper operation.
The HO2S requires a minimum temperature to operate properly and provide a closed loop fuel control system. The HO2S contains the heater element to reduce its warming-up time and ensure its performance during all driving conditions.
The oxygen sensor generates a voltage that indicates the difference between the oxygen content of the exhaust stream and the oxygen content of ambient air. When the exhaust stream is "rich", there is more oxygen in the ambient air than in the exhaust stream, so the voltage will be higher.
DTC DESCRIPTION
The response time of an O2 sensor can be impacted by two factors: temperature and poisoning. Poisoning of the O2 sensor is the primary failure mode of O2 sensor response time. Poisoning can come from many sources: silicone from gaskets or even in the fuel, phosphorous from engine oil, carbon from operating in a cooler environment or lead from the fuel. Most poisoning failures have the potential to clear up after the source of the poisoning has been removed. However, sometimes the poisoning may be so severe that the damage is irreversible. Checking output signals from HO2S under detecting condition, if an output signal is out of threshold, PCM sets P0133.
DTC Detecting Condition:
Specification:
Schematic Diagram:
SIGNAL WAVEFORM AND DATA
Signal Waveform And Data:
After warming-up, if accelerator pedal is released suddenly around 4000 rpm, the HO2S signal reading will be lower than 200 mV resulting from Fuel cut-off for the moment. Conversely, if suddenly accelerator pedal is depressed, HO2S signal reading will be around 0.6 V - 1.0 V. At idle, HO2S signal will switch from lean to rich normally.
MONITOR SCANTOOL DATA
1. Connect Scantool & Engine "ON"
2. Warm up the engine to normal operating temperature.
3. Monitor HO2S voltage (B1/S1) parameter on scantool
Specification : Voltage will vary from 0.1 to 0.9 V
4. Is the HO2S parameter displayed within specifications?
YES - Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
NO - Go to "Component Inspection" procedure.
COMPONENT INSPECTION
1. Visual Inspection of HO2S
1. Visually/physically inspect following items:
- Inspect the front HO2S for Contaminated, deteriorated or aged Front HO2S
- If contamination is evident on the HO2S, replace contaminated sensor
2. Is the HO2S visually / physically O.K?
YES - Go to "Check Performance of HO2S".
NO - Substitute with a known - good HO2S and check for proper operation. If the problem is corrected, replace HO2S and go to "Verification of Vehicle Repair" procedure.
2. Check performance of HO2S
1. Connect scantool & Engine "ON"
2. Warm-up the engine to normal engine temperature.
3. Monitor signal waveform of HO2S with scantool.
Specification:
4. Is the sensor signal switching properly?
YES - Substitute with a known - good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.
NO - Substitute with a known - good HO2S and check for proper operation. If the problem is corrected, replace HO2S and go to "Verification of Vehicle Repair" procedure.
NOTE: There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by PCM. Before or after testing PCM on the vehicle, use this function to reuse the PCM on the others.
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code (DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs.
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions.
4. Monitor that all readiness test have been verified as "Complete".
5. Are any DTCs present?
YES - Go to the applicable troubleshooting procedure.
NO - System is performing to specification at this time.