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Home >> Mazda >> 2010 >> 3 i Touring, 2.0 F, Standard >> Repair and Diagnosis >> Engine Performance >> System >> On-Board Diagnostic [Engine Control System LF, L5] >> DTC P0140:00 >> Diagnostic Procedure

Diagnostic Procedure

DTC P0140:00 (LF, L5) DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 VERIFY SNAPSHOT DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED 
  • Have the snapshot data and DIAGNOSTIC MONITORING TEST RESULTS (A/F sensor, HO2S related) been recorded?
Yes Go to the next step.
No Record the snapshot data and DIAGNOSTIC MONITORING TEST RESULTS on repair order, then go to the next step.
2 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.
3 VERIFY RELATED PENDING CODE AND STORED DTC 
NOTE:
  • If fuel monitor DTC, DTC P0132:00 is retrieved, ignore it until P0140:00 is fixed.
  • Switch the ignition to off, then to ON (engine off).
  • Perform the DTC Reading Procedure and Pending Trouble Code Access Procedure.

    (See ON-BOARD DIAGNOSTIC TEST .)

  • Are any other DTCs present?
Yes Go to the applicable DTC inspection.
(See DTC TABLE .)
No Go to the next step.
4 IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA (MODE 2) 
  • Perform the Freeze Frame PID Data Access Procedure.

    (See ON-BOARD DIAGNOSTIC TEST .)

  • Is the DTC P0140:00 on FREEZE FRAME DATA (Mode 2)?
Yes Go to the next step.
No Go to the troubleshooting procedures for DTC on FREEZE FRAME DATA (Mode 2).
(See DTC TABLE .)
5 INSPECT HO2S CONNECTOR CONDITION 
  • Switch the ignition to 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 terminal and/or connector, then go to Step 14.
No Go to the next step.
6 INSPECT HO2S HEATER  Yes Replace the HO2S, then go to Step 14.
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION .)
No Go to the next step.
7 INSPECT HO2S SIGNAL CIRCUIT FOR SHORT TO GROUND 
  • HO2S connector is disconnected.
  • Inspect for continuity between HO2S terminal A (wiring harness-side) and body ground.
  • Is there continuity?
Yes If the short to ground circuit could be detected:
  • Repair or replace the wiring harness for a possible short to ground.

    If the short to ground circuit could not be detected:

  • Replace the PCM (short to ground in PCM internal circuit).

    (See PCM REMOVAL/INSTALLATION .)

  • Go to Step 14.
No Go to the next step.
8 INSPECT PCM CONNECTOR CONDITION 
  • Disconnect the PCM connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
Yes Repair or replace the terminal and/or connector, then go to Step 14.
No Go to the next step.
9 INSPECT GAS LEAKAGE FROM EXHAUST SYSTEM 
  • Reconnect the HO2S connector.
  • Visually inspect the exhaust system from exhaust manifold to HO2S.
  • Is there any leakage?
Yes Repair or replace the malfunctioning part according to the inspection results, then go to Step 14.
No Go to the next step.
10 INSPECT HO2S SIGNAL CIRCUIT FOR OPEN CIRCUIT 
  • Disconnect the HO2S connector.
  • HO2S and PCM connectors are disconnected.
  • Inspect for continuity between HO2S terminal A (wiring harness-side) and PCM terminal 2Q (wiring harness-side).
  • Is there continuity?
Yes Go to the next step.
No Repair or replace the wiring harness for a possible open circuit, then go to Step 14.
11 INSPECT SEALING OF ENGINE COOLANT PASSAGE  Yes Repair or replace the malfunctioning part according to the inspection results, then go to Step 14.
No Go to the next step.
12 INSPECT ENGINE COMPRESSION  Yes Repair or replace the malfunctioning parts according to the inspection results, then go to Step 14.
No Go to the next step.
13 INSPECT HO2S  Yes Replace the HO2S, then go to the next step.
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION .)
No Go to the next step.
14 VERIFY DTC TROUBLESHOOTING COMPLETED 
  • Make sure to reconnect all disconnected connectors.
  • Clear the DTC from the PCM memory using the M-MDS.

    (See AFTER REPAIR PROCEDURE .)

  • Start the engine and warm it up completely.
  • Perform the Pending Trouble Code Access Procedure.

    (See ON-BOARD DIAGNOSTIC TEST .)

  • 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.
15 VERIFY AFTER REPAIR PROCEDURE  Yes Go to the applicable DTC inspection.
(See DTC TABLE .)
No DTC troubleshooting completed.