An OBD Scan Tool will usually identify Oxygen Sensors by the Bank Number (B1 = Bank 1) and Sensor Number (S1 = Sensor 1). Bank 1 will always contain Cylinder 1, which is located closest to the front of the engine.
Part manufacturers often use different terms than scan tools to identify sensor positions. Regardless of the vehicle's engine orientation, the right or left bank is determined by viewing the engine from the rear (opposite the drive belts).
A
Upstream Sensor (Before Converter)
B
Downstream Sensor (After Converter)
C
Left or Front Upstream Sensor (Before Converter)
D
Right or Rear Upstream Sensor (Before Converter)
Common O2 Sensor Contaminants
Oxygen (O2) Sensors commonly fail due to contamination. When checking or replacing an O2 Sensor, visually inspect the sensor body to determine if it has been contaminated by a faulty part or substance upstream, and correct the fault before replacing the sensor.
ANTIFREEZE POISONING
Common Causes:
Cracked or warped cylinder head
Leaking cylinder head gasket
Leaking intake manifold gasket
Antifreeze Poisoned O2 Sensor
SILICONE POISONING
Common Causes:
Use of an improper silicone gasket sealant on the engine
STANDARD MOTOR PRODUCTS Warranty Information:Ignition Control Modules (except T-Series): 5 years / 50,000 miles; Intermotor Wire Sets: Limited Lifetime; T-Series Parts: 1 year / 12,000 miles; TechSmart Tools: 1 year from date of purchase; All Other Parts: 3 years / 36,000 milesWarranty Details
O2 Sensor Identification Guide
Common O2 Sensor Contaminants
