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Home >> Suzuki >> 2012 >> Equator RMZ-4 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Performance - VQ40DE - (2 Of 6) >> DTC P0139, P0159: Ho2S2 >> Diagnosis Procedure
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Diagnosis Procedure

DIAGNOSIS PROCEDURE MALFUNCTION A

Step Action YES NO
1  CHECK GROUND CONNECTIONS 
  1. Turn ignition switch OFF.
  2. Loosen and retighten three ground screws on the body. Refer to [POWER SUPPLY AND GROUND CIRCUIT CHECK ].
G06441364Courtesy of SUZUKI OF AMERICA CORP.

OK or NG 		 GO TO 2. Repair or replace ground connections.
2  CLEAR THE SELF-LEARNING DATA 

1) With SDT 

  1. Start engine and warm it up to normal operating temperature.
  2. Select "SELF-LEARNING CONT" in "Utility" mode with SDT.
  3. Clear the self-learning control coefficient by touching "CLEAR".
  4. Run engine for at least 10 minutes at idle speed. Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected? Is it difficult to start engine?

2) Without SDT 

  1. Start engine and warm it up to normal operating temperature.
  2. Turn ignition switch OFF.
  3. Disconnect mass air flow sensor harness connector, and restart and run engine for at least 5 seconds at idle speed.
    Fig 1: Identifying Mass Air Flow Sensor Harness Connector
    G06441371Courtesy of SUZUKI OF AMERICA CORP.
  4. Stop engine and reconnect mass air flow sensor harness connector.
  5. Check DTC P0102 is displayed.
  6. Erase the DTC memory. Refer to EMISSION-RELATED DIAGNOSTIC INFORMATION ITEMS .
  7. eck DTC P0000 is displayed.
  8. Run engine for at least 10 minutes at idle speed. Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected? Is it difficult to start engine?

Yes or No 		 Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to DTC P0171, P0174: Fuel Injection System Function  or DTC P0172, P0175: Fuel Injection System Function . GO TO 3.
3  CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
  1. urn ignition switch OFF.
  2. Disconnect heated oxygen sensor 2 harness connector.
    3. Fig 2: Identifying Oxygen Sensor 2 Harness Connector
    G00500680Courtesy of SUZUKI OF AMERICA CORP.
  3. Disconnect ECM harness connector.
  4. Check harness continuity between HO2S2 terminal 4 and ECM terminal 78. Refer to Wiring Diagram.

    5. Continuity should exist.

  5. Also check harness for short to ground and short to power.

OK or NG 		 GO TO 4. Repair open circuit or short to ground or short to power in harness or connectors.
4  CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
  1. Check harness continuity between ECM terminal and HO2S2 terminal as follows. Refer to Wiring Diagram.
    2. Fig 3: Wiring Diagram
    G00500681Courtesy of SUZUKI OF AMERICA CORP.

    Continuity should exist. 

  2. Check harness continuity between the following terminals and ground. Refer to Wiring Diagram.
    3. Fig 4: Wiring Diagram
    G00500681Courtesy of SUZUKI OF AMERICA CORP.

    Continuity should not exist. 

  3. Also check harness for short to power.

OK or NG 		 GO TO 5. Repair open circuit or short to ground or short to power in harness or connectors.
5  CHECK HEATED OXYGEN SENSOR 2 
Refer to [P0139, P0159 HO2S2 ].
OK or NG 		 GO TO 6. Replace malfunctioning heated oxygen sensor 2.
6  CHECK INTERMITTENT INCIDENT 
Refer to [SERVICE INFORMATION FOR ELECTRICAL INCIDENT: INTERMITTENT INCIDENT ]		 INSPECTION END   
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