PINPOINT TEST DW: Heated Oxygen Sensor (HO2S): Introduction

WARNING: This page is about a different car, the 2007 Mercury Mariner and 2007 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: This vehicle is equipped with high voltage cables, components, and wiring. The high voltage warning labels containing the high voltage symbol are located on each high voltage component. High voltage cables and wiring are orange in color. Certified rubber insulating gloves and a face shield must be worn when working with the high voltage cables, components, or wiring. The ignition key must be cycled to the OFF position for a minimum of 5 minutes, and the high voltage traction battery service disconnect plug placed in the servicing/shipping position before disconnecting the high voltage cables. Failure to follow these instructions may result in personal injury or death.

Do not disconnect, disable, or touch the high voltage cables, components, or wiring during the module reprogramming procedure because high voltage is present. The high voltage warning labels containing the high voltage symbol are located on each high voltage component. High voltage cables and wiring are orange in color. Failure to follow these instructions may result in personal injury or death.

WARNING: While conducting tests on a hot engine take all safety precautions to prevent skin contact with hot engine components. Failure to follow these instructions may result in personal injury.

Appropriate repair methods and procedures are essential for the safe, reliable operation of all motor vehicles, as well as the personal safety of the individual doing the work. This article provides general directions for repairing vehicles with tested, effective techniques. Following them helps to establish reliability. There are numerous variations in procedures, techniques, tools, and parts for repairing vehicles, as well as in the skill of the individual doing the work. This article cannot possibly anticipate all such variations and provide advice or cautions as to each. Accordingly, anyone who departs from the instructions provided in this article must first establish that they compromise neither their personal safety nor the vehicle integrity by their choice of methods, tools, or parts.

This pinpoint test is intended to diagnose the following:

HO2S/O2S (9F472)
HO2S/O2S (9G444)
harness circuits: HO2S, HO2S Heater, VPWR, and SIGRTN
powertrain control module (PCM) (12A650)

Fig 1: HO2S Location

Fig 2: Heated Oxygen Sensor Bank 1, Sensor 1 (HO2S11) Connector

Pin	Circuit
1	VPWR (Vehicle Power)
3	SIGRTN (Signal Return)
2	HO2S Heater (HO2S Heater)
4	HO2S Signal (HO2S Signal Circuit)

Fig 3: Heated Oxygen Sensor Bank 1, Sensor 1 (HO2S11) Connector

Pin	Circuit
1	VPWR (Vehicle Power)
3	SIGRTN (Signal Return)
2	HO2S Heater (HO2S Heater)
4	HO2S Signal (HO2S Signal Circuit)

Fig 4: Identifying 150 Pin PCM Harness Connectors/Terminals

Pin	Circuit
E30	HO2S11 (Heated Oxygen Sensor Bank 1, Sensor 1)
E49	HTR11 (Heater Oxygen Sensor Bank 1, Sensor 1)
E42	HO2S12 (Heated Oxygen Sensor Bank 1, Sensor 2)
E50	HTR12 (Heater Oxygen Sensor Bank 1, Sensor 2)
B35	VPWR (Vehicle Power)
E41	SIGRTN (Signal Return)