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Home >> Mercury >> 2009 >> Mariner Base, 2.5 7, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 7 (Engine Controls - Powertrain DTC Charts & Descriptions - (Hybrid)) >> Diagnostic Trouble Code (DTC) Charts and Descriptions >> DTC P0030: Ho2S Heater Control Circuit (Bank 1, Sensor 1)

DTC P0030: Ho2S Heater Control Circuit (Bank 1, Sensor 1)

WARNING: This page is about a different variant/trim than selected.
P0030 - HO2S HEATER CONTROL CIRCUIT (BANK 1, SENSOR 1)

Description:  The powertrain control module (PCM) monitors the heater in the heated oxygen sensor (HO2S) for correct operation. The PCM controls the heater on/off duty cycle to maintain a temperature of 780°C (1,436°F). The test fails when the sensor does not warm up to the required temperature in a calibrated amount of time. The test also fails when the PCM is not able to maintain the required temperature after the sensor is warm.
Possible Causes: 
  • Open UO2S circuit
  • Open UO2SGREF circuit
  • Open UO2SHTR circuit
  • UO2SHTR circuit short to voltage
  • Loose connection, and damaged or corroded terminals
  • Exhaust temperature significantly higher than expected
  • Damaged universal HO2S
Diagnostic Aids:  Inspect the connectors for signs of damage, water ingress, or corrosion.
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
All - GO to PINPOINT TEST DZ . GO to PINPOINT TEST DZ .