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Home >> Suzuki >> 2009 >> Equator RMZ-4 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (VQ40DE) - (4 Of 5) >> DTC P0138, P0158: Ho2S2 >> On Board Diagnosis Logic >> Malfunction B
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Malfunction B

To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the minimum voltage of sensor is sufficiently low during the various driving condition such as fuel-cut.

Fig 1: Heated Oxygen Sensor 2 Voltage Graph - Malfunction B
G06441348Courtesy of SUZUKI OF AMERICA CORP.
DTC DETECTING CONDITION AND POSSIBLE CAUSE

DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0138
0138 (Bank 1)
Heated oxygen sensor 2 circuit high voltage A) An excessively high voltage from the sensor is sent to ECM.
  • Harness or connectors (The sensor circuit is open or shorted)
  • Heated oxygen sensor 2
P0158
0158 (Bank 2)
B) The minimum voltage from the sensor is not reached to the specified voltage.
  • Harness or connectors (The sensor circuit is open or shorted)
  • Heated oxygen sensor 2
  • Fuel pressure
  • Fuel injector