LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Suzuki >> 2012 >> Equator Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine General Information & Diagnosis - Qr25DE (2 Of 5) >> DTC P0137: Ho2S2 >> Diagnosis Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis Procedure

DIAGNOSIS PROCEDURE CHART

Step Action YES NO
1  CHECK GROUND CONNECTIONS 
  1. Turn ignition switch OFF.
  2. Loosen and retighten two ground screws on the body. Refer to [POWER SUPPLY AND GROUND CIRCUIT CHECK ].
G00538109Courtesy 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 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.
G06444095Courtesy of SUZUKI OF AMERICA CORP.

  1. 4. Stop engine and reconnect mass air flow sensor harness connector.
  2. 5. Make sure DTC P0102 is displayed.
  3. 6. Erase the DTC memory.

    Refer to [EMISSION-RELATED DIAGNOSTIC INFORMATION ].

  4. 7. Make sure DTC P0000 is displayed.
  5. 8. Run engine for at least 10 minutes at idle speed.

    Is the 1st trip DTC P0171 detected? 

    Is it difficult to start engine? 


Yes or No 		 Perform trouble diagnosis for DTC P0171. Refer to DTC P0171: Fuel Injection System Function  . GO TO 3.
3  CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT 
  1. Turn ignition switch OFF.
  2. Disconnect heated oxygen sensor 2 harness connector.
G06444096Courtesy of SUZUKI OF AMERICA CORP.

  1. 3. Disconnect ECM harness connector.
  2. 4. Check harness continuity between ECM terminal 78 and HO2S2 terminal 4.

    Refer to WIRING DIAGRAM .

    Continuity should exist. 

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

OK or NG 		 GO TO 4. Repair open circuit, 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 74 and HO2S2 terminal 1.

    Refer to WIRING DIAGRAM .

    Continuity should exist. 

  2. Check harness continuity between ECM terminal 74 or HO2S2 terminal 1 and ground.

    Refer to WIRING DIAGRAM .

    Continuity should not exist. 

  3. Also check harness for short to power.

OK or NG 		 GO TO 5. Repair open circuit, short to ground or short to power in harness or connectors.
5  CHECK HEATED OXYGEN SENSOR 2 
Refer to [Component Inspection ].
OK or NG 		 GO TO 6. Replace heated oxygen sensor 2. Refer to EXHAUST SYSTEM: EXPLODED VIEW .
6  CHECK INTERMITTENT INCIDENT 
Refer to [SERVICE INFORMATION FOR ELECTRICAL INCIDENT: INTERMITTENT INCIDENT ]		 INSPECTION END   
scientia non olet · About LEMON Manuals