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Home >> Mazda >> 2010 >> 5 Touring, 2.3 L >> Repair and Diagnosis >> Engine Performance >> System >> On-Board Diagnostic [Engine Control System L3] >> DTC P0139 >> Diagnostic procedure
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Diagnostic procedure

DTC P0139 [L3] DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA (MODE 2) 
  • Is DTC P0139 on FREEZE FRAME DATA (Mode 2)?
 Yes Go to the next step.
No Go to troubleshooting for DTC on FREEZE FRAME DATA (Mode 2).
(See DTC TABLE .)
2 VERIFY FREEZE FRAME DATA (MODE 12) AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED 
  • Have FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS (A/F sensor, HO2S related) been recorded?
 Yes Go to the next step.
No Record the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS on repair order, then go to the next step.
3 VERIFY RELATED REPAIR INFORMATION AVAILABILITY 
  • Verify related Service Bulletins and/or on-line repair information availability.
  • Is any related repair information available?
 Yes Perform repair or diagnosis according to the available repair information.
  • If the vehicle is not repaired, go to the next step.
No Go to the next step.
4 VERIFY RELATED PENDING AND STORED DTC 
  • Turn the ignition switch off, then to the ON position (Engine off).
  • Verify pending and/or stored DTCs using the M-MDS.
  • Is DTC P0443 also present?
 Yes Go to DTC P0443 troubleshooting procedures, then go to Step 15.
No Go to the next step.
5 INSPECT INSTALLATION OF HO2S 
  • Inspect if the HO2S is loosely installed.
  • Is the sensor installed securely?
 Yes Go to the next step.
No Retighten the sensor, then go to Step 15.
6 INSPECT GAS LEAKAGE FROM EXHAUST SYSTEM 
  • Visually inspect if there is any gas leakage is found between the exhaust manifold and HO2S.
  • Is there gas leakage?
 Yes Repair or replace malfunctioning faulty exhaust part, then go to Step 15.
No Go to the next step.
7 INSPECT HO2S 
 Yes Inspect and repair A/F sensor related wiring harnesses. If wiring harness is normal, replace the HO2S, then go to Step 15.
No Go to the next step.
8 INSPECT PURGE SOLENOID VALVE 
 Yes Repair or replace malfunctioning part, according to inspection result.
Then go to Step 12.
No Go to the next step.
9 INSPECT LONG TERM FUEL TRIM 
  • Access PCM PID LONGFT1 using the M-MDS.
  • Compare it with FREEZE FRAME DATA (Mode 12) recorded at Step 1.
  • Is it below FFD value?
 Yes Engine is driven under rich condition. Go to the next step.
No Engine is driven under lean condition. Go to Step 11.
10 INSPECT FUEL LINE PRESSURE (Excessive fuel line pressure) 
  • Turn the ignition switch off.
  • Inspect fuel line pressure while the engine running.

    (See FUEL LINE PRESSURE INSPECTION .)

  • Is the fuel line pressure normal?
 Yes Go to Step 13.
No Inspect fuel pump maximum pressure and fuel return pipe for clogging.
(See FUEL PUMP UNIT INSPECTION .)
  • If there is any problem, repair or replace the parts.
  • If all items above are normal, replace fuel pump unit.

Then go to Step 15.
11 INSPECT FUEL LINE PRESSURE (Low fuel line pressure) 
  • Turn the ignition switch off.
  • Inspect fuel line pressure while the engine running.

    (See FUEL LINE PRESSURE INSPECTION .)

  • Is fuel line pressure normal?
 Yes Go to Step 15.
No Go to the next step.
12 INSPECT FUEL LINE FROM FUEL PUMP TO FUEL DISTRIBUTOR 
  • Visually inspect the fuel line for any leakage.
  • Is there fuel leakage?
 Yes Replace the fuel line, then go to Step 15.
No Inspect the fuel filters for the following:
  • Foreign materials or stain inside fuel filter (low-pressure side)

Perform the following actions according to the result.
  • If foreign material or stain is found inside fuel filter (low-pressure side), clean the fuel tank and filter.
  • If normal, replace fuel pump unit.

Then go to Step 15.
13 INSPECT SEALING OF ENGINE COOLANT PASSAGE 
 Yes Repair or replace the malfunctioning part according to inspection results.
Then go to Step 15.
No Go to the next step.
14 INSPECT ENGINE COMPRESSION 
 Yes Go to the next step.
No Perform engine overhaul for repairs, then go to the next step.
15 VERIFY TROUBLESHOOTING OF DTC P0139 COMPLETED 
  • Make sure to reconnect all disconnected connectors.
  • Turn the ignition switch to the ON position. (Engine off)
  • Clear the DTC from the memory using M-MDS.
  • Perform the "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 .)
No Go to the next step.
16 VERIFY AFTER REPAIR PROCEDURE 
 Yes Go to the applicable DTC troubleshooting.
(See DTC TABLE .)
No Troubleshooting completed.
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