Dtc P0139[L3 With Tc] - Mazda CX-7 2007 Workshop Manual

DTC P0139[L3 WITH TC]

DTC P0139 Rear HO2S circuit problem
• The PCM monitors the rich (0.4 V) to lean (0.3 V) response time of the rear HO2S. The PCM measures the
response time when the following conditions are met. The PCM determines that the rear HO2S response
deteriorated when the measured response time is more than the threshold value (130 ms) five consecutive
times.
MONITORING CONDITIONS
— HO2S heater, HO2S, and TWC Repair Verification Drive Mode or EGR, HO2S heater, HO2S, TWC, and
EVAP System Repair Verification Drive Mode
— The following conditions are met:
• Fuel cut during deceleration
• Engine speed is more than 500 rpm.
• Engine coolant temperature is more than 70 °C {158 °F}.
• HO2S (rear) output voltage is more than 0.4 V.
• The PCM monitors for a time-out malfunction (when rear HO2S remains above 0.3 V for longer than a
specified period of time during fuel cut control). The PCM measure the amount of time from when the
following conditions are met until the rear HO2S output voltage drops below 0.3 V. The PCM determines
that a HO2S time-out malfunction has occurred when the detected time is more than the threshold value
DETECTION
(6.4 s) three consecutive times.
CONDITION
MONITORING CONDITIONS
— HO2S heater, HO2S, and TWC Repair Verification Drive Mode or EGR, HO2S heater, HO2S, TWC, and
EVAP System Repair Verification Drive Mode
— The following conditions are met:
• Fuel cut during deceleration
• Engine speed is more than 500 rpm.
• Engine coolant temperature is more than 70 °C {158 °F}.
• HO2S (rear) is activated (more than 0.55 V).
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.
• DTCs are stored in the PCM memory.
• Rear HO2S deterioration
• Rear HO2S malfunction
• Rear HO2S looseness
• Pressure regulator (built-in fuel pump unit) malfunction
• Fuel pump malfunction
• Fuel filter (built-in fuel pump unit) clogged or restricted
POSSIBLE
• Fuel leakage on fuel line from fuel delivery pipe to fuel pump
CAUSE
• Exhaust system leakage
• Purge solenoid valve malfunction
• Improper connection of purge solenoid hoses
• Insufficient compression
• Engine malfunction (Leakage engine coolant)
Diagnostic procedure
STEP
1 VERIFY FREEZE FRAME DATA AND
DIAGNOSTIC MONITORING TEST RESULTS
HAVE BEEN RECORDED
• Have the FREEZE FRAME DATA and
DIAGNOSTIC MONITORING TEST RESULTS
(HO2S related) been recorded?
2 VERIFY RELATED REPAIR INFORMATION
AVAILABILITY
• Verify related Service Bulletins and/or-line
repair information availability.
• Is any related repair information available?
01-02–90
ON-BOARD DIAGNOSTIC [L3 WITH TC]
INSPECTION
Yes Go to the next step.
No Record the FREEZE FRAME DATA and DIAGNOSTIC
MONITORING TEST RESULTS on the repair order, then
go to the next step.
Yes Perform the repair or diagnosis according to the available
Service Information.
• If the vehicle is not repaired, go to the next step.
No Go to the next step.
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