DTC P0133

A/F sensor circuit problem

DETECTION CONDITION

The PCM monitors the peak differential value of oxygen sensor signal after A/F fluctuation being provided when the following conditions are met. If the peak differential value is lower than the threshold value.
The PCM determines that A/F sensor circuit is slow.
MONITORING CONDITIONS
- PCM Adaptive Memory Production, EGR System, A/F Sensor Heater, HO2S Heater, A/F Sensor, HO2S, and TWC Repair Verification Drive Mode
- Following conditions are met:
  - A/F sensor heater monitor is completed.
  - Fuel system loop status is closed loop fuel control.
- Engine speed: 1, 750-3, 500 rpm
- Charging efficiency: 25-63% (at engine speed: 2, 500 rpm )
- Engine coolant temperature: above 70°C {158°F}

Diagnostic support note

This is an intermittent monitor (A/F sensor, HO2S).
The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
FREEZE FRAME DATA (Mode 2/Mode 12) is available.
The DTC is stored in the PCM memory.

POSSIBLE CAUSE

A/F sensor malfunction
- A/F sensor connector or terminals malfunction
- A/F sensor looseness
- Exhaust system leakage
Fuel supply system malfunction or improper fuel line pressure
- Fuel leakage in fuel line between fuel distribution pipe and fuel pump
- Clogged or restricted fuel filter (built-in fuel pump unit)
- Pressure regulator (built-in fuel pump unit) malfunction
- Fuel pump malfunction
Purge system malfunction
- Purge solenoid valve malfunction
- Improper connection purge solenoid hose
Engine malfunction (Engine coolant leakage)
- Engine coolant leakage to combustion chamber
- Insufficient compression
A/F sensor deterioration
PCM malfunction

DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA (MODE 12) AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED Have the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS (A/F sensor, HO2S related) been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
2	VERIFY RELATED SERVICE BULLETINS AVAILABILITY Verify related Service Bulletins availability. Is any related Service Bulletins available?	Yes	Perform the repair or diagnosis according to the available Service Bulletins. If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	VERIFY RELATED PENDING CODE AND STORED DTC Turn the ignition switch off, then to the ON position (Engine off). Verify related PENDING CODE and stored DTC. Is the DTC P0443 also present?	Yes	Go to the applicable DTC inspection. (See DTC P0443 ).
3		No	Go to the next step.
4	IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA (MODE 2) Is the DTC P0133 on FREEZE FRAME DATA (Mode 2)?	Yes	Go to the next step.
4		No	Go to the troubleshooting procedures for DTC on FREEZE FRAME DATA (Mode 2). (See DTC TABLE ).
5	INSPECT A/F SENSOR CONNECTOR AND TERMINALS Turn the ignition switch off. Disconnect the A/F sensor connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Is there any malfunction?	Yes	Repair or replace the connector or terminals, then go to Step 15.
5		No	Go to the next step.
6	INSPECT INSTALLATION OF A/F SENSOR Inspect if the A/F sensor is loosely installed. Is the A/F sensor installed securely?	Yes	Go to the next step.
6		No	Retighten the A/F sensor, then go to Step 15. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION ).
7	INSPECT GAS LEAKAGE FROM EXHAUST SYSTEM Visually inspect if there is any gas leakage between the exhaust manifold and A/F sensor. Is there gas leakage?	Yes	Repair or replace any malfunctioning exhaust part, then go to Step 15.
7		No	Go to the next step.
8	INSPECT FUEL LINE PRESSURE Turn the ignition switch off. Inspect the fuel line pressure while the engine running. (See FUEL LINE PRESSURE INSPECTION ). Is the fuel line pressure normal?	Yes	Go to Step 12.
8		No	Go to the next step.
9	INSPECT FUEL LINE LEAKAGE Visually inspect the leakage from fuel line between fuel distribution pipe to fuel pump unit. Is there fuel leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 15.
9		No	Go to the next step.
10	INSPECT FUEL FILTER Visually inspect the foreign, materials or strain inside the fuel filter. Is there any foreign materials or stain?	Yes	Remove the foreign materials or replace the fuel filter, then go to Step 15.
10		No	Replace the fuel pump unit, then go to Step 15. (See FUEL PUMP UNIT REMOVAL/INSTALLATION ).
11	INSPECT PURGE SOLENOID VALVE Inspect the purge solenoid valve and vacuum hose connection. (See PURGE SOLENOID VALVE INSPECTION ). Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 15.
11		No	Go to the next step.
12	INSPECT SEALING OF ENGINE COOLANT PASSAGE Perform the "ENGINE COOLANT LEAKAGE INSPECTION". (See ENGINE COOLANT LEAKAGE INSPECTION ). Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 15.
12		No	Go to the next step.
13	INSPECT ENGINE COMPRESSION Inspect the engine compression. (See COMPRESSION INSPECTION ). Is there any malfunction?	Yes	Overhaul the engine, then go to Step 15.
13		No	Go to the next step.
14	INSPECT A/F SENSOR Inspect the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR INSPECTION ). Is there any malfunction?	Yes	Inspect the A/F sensor relate wiring harness. If the wiring harness has a malfunction: Repair or replace the suspected wiring harness. If the wiring harness normal: Replace the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION ). Go to the next step.
14		No	Go to the next step.
15	VERIFY TROUBLESHOOTING OF DTC P0133 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the M-MDS or equivalent. Perform the Drive Mode 03 (PCM Adaptive Memory Production, EGR System, A/F Sensor Heater, HO2S Heater, A/F Sensor, HO2S, and TWC Repair Verification Drive Mode). (See OBD-II DRIVE MODE ). Is the PENDING CODE for this DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION ).
15		No	Go to the next step.
16	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE ). Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE ).
16		No	DTC troubleshooting completed.