DTC P0139

HO2S circuit slow response

DETECTION CONDITION

The PCM monitors the rich (0.55 V ) to lean (0.3 V ) response time of the HO2S. The PCM measures the response time when the following conditions are met. The PCM determines a HO2S response deterioration malfunction when the measured response time is more than 110 ms for 2 of 3 times.
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:
  - During deceleration fuel cut
  - Estimated temperature of the zirconia element inside the HO2S: above 450°C {842°F}
The PCM monitors for a time-out malfunction (when HO2S remains above 0.2 V for longer than a specified period of time during fuel cut control). The PCM measures the amount of time from when the following conditions are met until the HO2S output voltage drops below 0.2 V. The PCM determines a HO2S timeout malfunction when the detected time is more than 4 s for 2 of 3 times.
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
  - During deceleration fuel cut
  - Estimated temperature of the zirconia element inside the HO2S: above 450°C {842°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

HO2S malfunction
- HO2S connector or terminals malfunction
- Looseness HO2S
- Leakage exhaust system
- HO2S deterioration
Fuel supply system malfunction or improper fuel line pressure
- Fuel leakage on fuel line from fuel distribution pipe and fuel pump
- Fuel fitter (built-in fuel pump unit) clogged or restricted
- Pressure regulator (built-in fuel pump unit) malfunction
- Fuel pump malfunction
Purge system malfunction
- Purge solenoid valve malfunction
- Purge solenoid hoses improper connection
Engine malfunction
- Leakage engine coolant to combustion chamber
- Insufficient compression
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 P0139 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 HO2S CONNECTOR AND TERMINALS Turn the ignition switch off. Disconnect the HO2S 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 HO2S Inspect if the HO2S is loosely installed. Is the HO2S installed securely?	Yes	Go to the next step.
6		No	Retighten the HO2S, then go to Step 15. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION ).
7	INSPECT GAS LEAKAGE FROM EXHAUST SYSTEM Visually inspect if there is any gas leakage between the exhaust manifold and HO2S. 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 HO2S Inspect the HO2S. (See HEATED OXYGEN SENSOR (HO2S) INSPECTION ). Is there any malfunction?	Yes	Replace the HO2S, then go to Step 15. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION ).
8		No	Go to the next step.
9	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.
9		No	Go to the next step.
10	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.
10		No	Go to the next step.
11	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.
11		No	Replace the fuel pump unit, then go to Step 15. (See FUEL PUMP UNIT REMOVAL/INSTALLATION ).
12	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.
12		No	Go to the next step.
13	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.
13		No	Go to the next step.
14	INSPECT ENGINE COMPRESSION Inspect the engine compression. (See COMPRESSION INSPECTION ). Is there any malfunction?	Yes	Overhaul the engine, then go to the next step.
14		No	Go to the next step.
15	VERIFY TROUBLESHOOTING OF DTC P0139 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.