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

WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

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 voltage 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 .