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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 P0135: O2 Heater Circuit (Bank 1, Sensor 1)

DTC P0135: O2 Heater Circuit (Bank 1, Sensor 1)

WARNING: This page is about a different variant/trim than selected.
P0135 - O2 HEATER CIRCUIT (BANK 1, SENSOR 1)

Description:  During testing the universal heated oxygen sensor (HO2S) heaters are checked for open and short circuits and excessive current draw. The test fails when the current draw exceeds a calibrated limit or an open or short circuit is detected.
Possible Causes: 
  • Short to VPWR in the harness or HO2S
  • Water in the harness connector
  • Open VPWR circuit
  • Open UO2SHTR circuit
  • Open GND circuit
  • Low battery voltage
  • Corrosion or incorrect harness connections
  • 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 .