Pinpoint Tests DW: Heated Oxygen Sensor (Ho2S): Introduction

WARNING: TO PREVENT THE RISK OF HIGH-VOLTAGE SHOCK, ALWAYS FOLLOW PRECISELY ALL WARNINGS AND SERVICE INSTRUCTIONS, INCLUDING INSTRUCTIONS TO DEPOWER THE SYSTEM. THE HIGH-VOLTAGE SYSTEM UTILIZES APPROXIMATELY 300 VOLTS DC, PROVIDED THROUGH HIGH-VOLTAGE CABLES TO ITS COMPONENTS AND MODULES. THE HIGH-VOLTAGE CABLES AND WIRING ARE IDENTIFIED BY ORANGE HARNESS TAPE OR ORANGE WIRE COVERING. ALL HIGH-VOLTAGE COMPONENTS ARE MARKED WITH HIGH-VOLTAGE WARNING LABELS WITH A HIGH-VOLTAGE SYMBOL. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN SERIOUS PERSONAL INJURY OR DEATH.

This pinpoint test is intended to diagnose the following:

exhaust leaks
HO2S/O2S (9G444)
harness circuits: HO2S12, HTR12, VPWR, and SIGRTN
PCM (12A650)

Fig 1: Heated Oxygen Sensor (HO2S) Connector

Courtesy of FORD MOTOR CO.

Pin	Circuit
3	SIGRTN (Signal Return)
2	HTR12 (Heater Oxygen Sensor Bank 1, Sensor 2)
4	HO2S12 (Heated Oxygen Sensor Bank 1, Sensor 2)
1	VPWR (Vehicle Power)

Fig 2: Powertrain Control Module (PCM) Connector

Courtesy of FORD MOTOR CO.

Pin	Circuit
E9	SIGRTN (Signal Return)
E35	HTR12 (Heater Oxygen Sensor Bank 1, Sensor 2)
E21	HO2S12 (Heated Oxygen Sensor Bank 1, Sensor 2)