California Emission Regulation Applicable Model: Notes

DTC P0139 (LF, L3) DETECTION CONDITION AND POSSIBLE CAUSES

DTC P0139	Middle HO2S circuit problem
DETECTION CONDITION	The PCM monitors inversion cycle period, middle HO2S output voltage inclination. The PCM detects that the voltage inclinations are below threshold consecutive 5 times when following conditions are met, the PCM determines that circuit has malfunction. Under the following monitoring conditions, if 0.3 V or more is detected three times even if fuel cut is performed for 3 s or more , a circuit malfunction is determined. MONITORING CONDITIONS PCM Adaptive Memory Production, HO2S heater, HO2S, and TWC Repair Verification Drive Mode Following conditions are met: Engine speed is above 500 rpm . Engine coolant temperature is above 70°C {158°F} . Diagnostic support note This is an intermittent monitor. (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. DIAGNOSTIC MONITORING TEST RESULTS is available. PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in the PCM memory.
POSSIBLE CAUSE	Middle HO2S deterioration Middle HO2S malfunction Looseness middle HO2S Pressure regulator (built-in fuel pump unit) malfunction Fuel pump malfunction Fuel filter (built-in fuel pump unit) clogged or restricted Fuel leakage on fuel line from fuel distribution pipe and fuel pump Leakage exhaust system Purge solenoid valve malfunction Purge solenoid hoses improper connection Insufficient compression Engine malfunction (Leakage engine coolant)

DTC P0139

Middle HO2S circuit problem

DETECTION CONDITION

The PCM monitors inversion cycle period, middle HO2S output voltage inclination. The PCM detects that the voltage inclinations are below threshold consecutive 5 times when following conditions are met, the PCM determines that circuit has malfunction. Under the following monitoring conditions, if 0.3 V or more is detected three times even if fuel cut is performed for 3 s or more , a circuit malfunction is determined.
MONITORING CONDITIONS
- PCM Adaptive Memory Production, HO2S heater, HO2S, and TWC Repair Verification Drive Mode
- Following conditions are met:
  - Engine speed is above 500 rpm .
  - Engine coolant temperature is above 70°C {158°F} .

Diagnostic support note

This is an intermittent monitor. (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.
DIAGNOSTIC MONITORING TEST RESULTS is available.
PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle.
FREEZE FRAME DATA is available.
DTC is stored in the PCM memory.

POSSIBLE CAUSE

Middle HO2S deterioration
Middle HO2S malfunction
Looseness middle HO2S
Pressure regulator (built-in fuel pump unit) malfunction
Fuel pump malfunction
Fuel filter (built-in fuel pump unit) clogged or restricted
Fuel leakage on fuel line from fuel distribution pipe and fuel pump
Leakage exhaust system
Purge solenoid valve malfunction
Purge solenoid hoses improper connection
Insufficient compression
Engine malfunction (Leakage engine coolant)