Heated Oxygen Sensor (HO2S) 1 Connector End View/Part Information/Terminal Identification

Courtesy of GENERAL MOTORS CORP.
Connector Part Information		AMP 174257 4-Way M 070 Series Econoseal J MK-2 Plug Assembly 4P (BK)
Pin	Wire Color	Circuit No.	Function
1	D-BU/BK	429	Heated Oxygen Sensor (HO2S) 1 Signal
2	BN	50	Heated Oxygen Sensor (HO2S) 1 Heater Control
3	WH	428	Heated Oxygen Sensor (HO2S) 1 Low Reference
4	PK/D-BU	1734	Main Relay Output