2013 Toyota Venza Oxygen Sensors

Refine by:
See All
See All

Shop Catalog

Showing 1 - 15 of 44 results
Display item:
15
30
45
Sort by:
After Catalytic Converter Oxygen Sensor, B1S2, Sold Individually, 4-wire, 4 Cyl 2.7L
Part Number: REPT960903
Guaranteed to Fit
$28.49
Vehicle Fitment
  • 2013 Toyota Venza XLE 4 Cyl 2.7L B1S2
  • 2013 Toyota Venza AWD 4 Cyl 2.7L B1S2
  • 2013 Toyota Venza LE 4 Cyl 2.7L B1S2
  • 2013 Toyota Venza Base 4 Cyl 2.7L B1S2
Product Details
Location : After Catalytic ConverterNotes : Downstream (After Catalytic converter)Type : 4-wireQuantity Sold : Sold IndividuallyProduct Fit : Direct FitWire Length : 14.17 in. Wire LengthThread Size : M18-1.5 Thread SizeMounting Style : Threaded-in Mounting StyleHex Size : 7/8 in. Hex SizeInterchange Part Number : 25024420Connector Gender : Male ConnectorWarranty : 1-year DriveWire unlimited-mileage warrantyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Returns Policy : 30-Day Return Policy
After Catalytic Converter Oxygen Sensor, B1S2, Sold individually, 4-wire, 4 Cyl 2.7L
Part Number: JT960903
Guaranteed to Fit
$28.99
Vehicle Fitment
  • 2013 Toyota Venza XLE 4 Cyl 2.7L B1S2
  • 2013 Toyota Venza AWD 4 Cyl 2.7L B1S2
  • 2013 Toyota Venza LE 4 Cyl 2.7L B1S2
  • 2013 Toyota Venza Base 4 Cyl 2.7L B1S2
Product Details
Location : After Catalytic ConverterNotes : Downstream (After Catalytic converter)Type : 4-wireQuantity Sold : Sold IndividuallyProduct Fit : Direct FitWire Length : 14.17 in. Wire LengthThread Size : M18-1.5 Thread SizeMounting Style : Threaded-in Mounting StyleHex Size : 7/8 in. Hex SizeInterchange Part Number : 25024420Connector Gender : Male ConnectorWarranty : 1-year JC Whitney unlimited-mileage warrantyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Returns Policy : 30-Day Return Policy
Before Catalytic Converter Oxygen Sensor, B1S1, Sold individually, 4 Cyl 2.7L
Part Number: JDL96090006
Guaranteed to Fit
$32.99
Vehicle Fitment
  • 2013 Toyota Venza XLE 6 Cyl 3.5L
  • 2013 Toyota Venza XLE 4 Cyl 2.7L B1S1
  • 2013 Toyota Venza LE 4 Cyl 2.7L B1S1
  • 2013 Toyota Venza Limited 6 Cyl 3.5L
  • 2013 Toyota Venza Base 4 Cyl 2.7L B1S1
  • 2013 Toyota Venza AWD 6 Cyl 3.5L
  • 2013 Toyota Venza LE 6 Cyl 3.5L
  • 2013 Toyota Venza AWD 4 Cyl 2.7L B1S1
  • 2013 Toyota Venza Base 6 Cyl 3.5L
Product Details
Location : Before Catalytic ConverterNotes : HeatedQuantity Sold : Sold IndividuallyProduct Fit : Direct FitWire Length : 16.73 in. Wire LengthInterchange Part Number : 25054084Connector Gender : MaleWarranty : 1-year JC Whitney unlimited-mileage warrantyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Returns Policy : 30-Day Return Policy
Before Catalytic Converter Oxygen Sensor, Sold Individually, 6 Cyl 3.5L
Part Number: DL96090006
Guaranteed to Fit
$25.49
Vehicle Fitment
  • 2013 Toyota Venza XLE 6 Cyl 3.5L
  • 2013 Toyota Venza XLE 4 Cyl 2.7L B1S1
  • 2013 Toyota Venza LE 4 Cyl 2.7L B1S1
  • 2013 Toyota Venza Limited 6 Cyl 3.5L
  • 2013 Toyota Venza Base 4 Cyl 2.7L B1S1
  • 2013 Toyota Venza AWD 6 Cyl 3.5L
  • 2013 Toyota Venza LE 6 Cyl 3.5L
  • 2013 Toyota Venza AWD 4 Cyl 2.7L B1S1
  • 2013 Toyota Venza Base 6 Cyl 3.5L
Product Details
Location : Before Catalytic ConverterNotes : HeatedQuantity Sold : Sold IndividuallyProduct Fit : Direct FitWire Length : 16.73 in. Wire LengthInterchange Part Number : 25054084Connector Gender : MaleWarranty : 1-year DriveWire unlimited-mileage warrantyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Returns Policy : 30-Day Return Policy
2-Piece Kit After Primary Catalytic Converter Catalytic Converter, 3.5L 6Cyl, Federal EPA Standard, 46-State Legal (Cannot ship to CA, CO, NY or ME), Firewall Side, Naturally Aspirated,  Includes (1) Catalytic Converter and (1) Oxygen Sensor
Part Number: KIT-070324-R063
Guaranteed to Fit
$246.99
Vehicle Fitment
  • 2013 Toyota Venza XLE 6 Cyl 3.5L Firewall Side
  • 2013 Toyota Venza AWD 6 Cyl 3.5L Firewall Side
  • 2013 Toyota Venza LE 6 Cyl 3.5L Firewall Side
  • 2013 Toyota Venza Base 6 Cyl 3.5L Firewall Side
  • 2013 Toyota Venza Limited 6 Cyl 3.5L Firewall Side
Product Details
Location : After Primary Catalytic ConverterEmissions : Federal EPA Standard, 46-State Legal (Cannot ship to CA, CO, NY or ME)Components : (1) Catalytic Converter and (1) Oxygen SensorRestricted States : California|Colorado|New York|MaineType : Manifold ConverterProduct Fit : Direct FitRecommended Use : OE ReplacementQuantity Sold : 2-Piece KitEPA : N/TB6000/501-430Gasket Included : With GasketOxygen Sensor Ports : Factory OE PortsOxygen Sensor Port Location : Factory OE LocationsWarranty : 1-year JC Whitney unlimited-mileage warrantyReturns Policy : 30-Day Return PolicyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Interchange Part Number : 17165, 40673, 674847, 49693, ARBT960915Tube Material : Aluminized Steel
2-Piece Kit After Primary Catalytic Converter Catalytic Converter, 3.5L 6Cyl, Federal EPA Standard, 46-State Legal (Cannot ship to CA, CO, NY or ME), Radiator Side, Naturally Aspirated,  Includes (1) Catalytic Converter and (1) Oxygen Sensor
Part Number: KIT-070324-R113
Guaranteed to Fit
$260.99
Vehicle Fitment
  • 2013 Toyota Venza XLE 6 Cyl 3.5L Radiator Side
  • 2013 Toyota Venza AWD 6 Cyl 3.5L Radiator Side
  • 2013 Toyota Venza LE 6 Cyl 3.5L Radiator Side
  • 2013 Toyota Venza Base 6 Cyl 3.5L Radiator Side
  • 2013 Toyota Venza Limited 6 Cyl 3.5L Radiator Side
Product Details
Location : After Primary Catalytic ConverterEmissions : Federal EPA Standard, 46-State Legal (Cannot ship to CA, CO, NY or ME)Components : (1) Catalytic Converter and (1) Oxygen SensorRestricted States : California|Colorado|New York|MaineType : Manifold ConverterProduct Fit : Direct FitRecommended Use : OE ReplacementQuantity Sold : 2-Piece KitEPA : N/TB6000/501-430Gasket Included : With GasketOxygen Sensor Ports : Factory OE PortsOxygen Sensor Port Location : Factory OE LocationsWarranty : 1-year JC Whitney unlimited-mileage warrantyReturns Policy : 30-Day Return PolicyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Interchange Part Number : 17160, 40672, 674846, ARBT960915Tube Material : Aluminized Steel
After Catalytic Converter Oxygen Sensor, B1S2, Sold individually, 4-wire, 4 Cyl 2.7L, Walker Products Original Equipment Base Sensor - After Catalytic Converter
Part Number: 25024420
Guaranteed to Fit
$59.49
Vehicle Fitment
  • 2013 Toyota Venza XLE 4 Cyl 2.7L B1S2
  • 2013 Toyota Venza AWD 4 Cyl 2.7L B1S2
  • 2013 Toyota Venza LE 4 Cyl 2.7L B1S2
  • 2013 Toyota Venza Base 4 Cyl 2.7L B1S2
Product Details
Location : After Catalytic ConverterNotes : HeatedType : 4-wireQuantity Sold : Sold IndividuallyProduct Fit : Direct FitWire Length : 14.17 in. Wire LengthInterchange Part Number : REPT960903Warranty : 90-day Walker Products limited warrantyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Series : Walker Products Original Equipment Base Sensor
OE Replacement Series Oxygen Sensor, Sold individually 4-wire
Part Number: BS15672
Guaranteed to Fit
$59.99
Vehicle Fitment
  • 2013 Toyota Venza XLE 6 Cyl 3.5L
  • 2013 Toyota Venza Limited 6 Cyl 3.5L
  • 2013 Toyota Venza AWD 6 Cyl 3.5L
  • 2013 Toyota Venza LE 6 Cyl 3.5L
  • 2013 Toyota Venza Base 6 Cyl 3.5L
Product Details
Location : Driver Side, After Catalytic ConverterType : 4-wireQuantity Sold : Sold IndividuallyProduct Fit : Direct FitWire Length : 11.8 in. Wire LengthThread Size : 18 mm Thread SizeMounting Style : Threaded-in Mounting StyleHex Size : 22 mm Hex SizeInterchange Part Number : 13441, 2344626Connector Gender : Male ConnectorWarranty : 1-year Bosch limited warrantyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Promotions : CarParts EuroEcomm Landing Page : EuroSeries : OE Replacement Series
After Catalytic Converter Oxygen Sensor, Eng. Designation: 1AR-FE, FI, Naturally Aspirated, GAS, Sold individually, 4-wire, 4 Cyl 2.7L, Walker Products Aftermarket Base Sensor - After Catalytic Converter
Part Number: WKP35034501
Guaranteed to Fit
$53.99
Vehicle Fitment
  • 2013 Toyota Venza XLE 4 Cyl 2.7L Eng. Designation: 1AR-FE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza AWD 4 Cyl 2.7L Eng. Designation: 1AR-FE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza LE 4 Cyl 2.7L Eng. Designation: 1AR-FE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza Base 4 Cyl 2.7L Eng. Designation: 1AR-FE, FI, Naturally Aspirated, GAS
Product Details
Location : After Catalytic ConverterNotes : HeatedType : 4-wireQuantity Sold : Sold IndividuallyProduct Fit : Direct FitWire Length : 14.17 in. Wire LengthWarranty : 90-day Walker Products limited warrantyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Series : Walker Products Aftermarket Base Sensor
After Secondary Catalytic Converter Oxygen Sensor, Eng. Designation: 2GRFE, FI, Naturally Aspirated, GAS, Sold individually, 4-wire, 6 Cyl 3.5L, Walker Products Aftermarket Base Sensor - After Secondary Catalytic Converter
Part Number: WKP35034099
Guaranteed to Fit
$39.99
Vehicle Fitment
  • 2013 Toyota Venza XLE 6 Cyl 3.5L Eng. Designation: 2GRFE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza Limited 6 Cyl 3.5L Eng. Designation: 2GRFE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza AWD 6 Cyl 3.5L Eng. Designation: 2GRFE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza LE 6 Cyl 3.5L Eng. Designation: 2GRFE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza Base 6 Cyl 3.5L Eng. Designation: 2GRFE, FI, Naturally Aspirated, GAS
Product Details
Location : After Secondary Catalytic ConverterNotes : HeatedType : 4-wireQuantity Sold : Sold IndividuallyProduct Fit : Direct FitWire Length : 13.78 in. Wire LengthWarranty : 90-day Walker Products limited warrantyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Series : Walker Products Aftermarket Base Sensor
Before Catalytic Converter Oxygen Sensor, Eng. Designation: 2GRFE, FI, Naturally Aspirated, GAS, Sold individually, 4-wire, 6 Cyl 3.5L, Walker Products Aftermarket Base Sensor - Before Catalytic Converter
Part Number: WKP35064031
Guaranteed to Fit
$94.49
Vehicle Fitment
  • 2013 Toyota Venza XLE 6 Cyl 3.5L Eng. Designation: 2GRFE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza XLE 4 Cyl 2.7L Eng. Designation: 1AR-FE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza LE 4 Cyl 2.7L Eng. Designation: 1AR-FE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza Limited 6 Cyl 3.5L Eng. Designation: 2GRFE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza Base 4 Cyl 2.7L Eng. Designation: 1AR-FE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza AWD 6 Cyl 3.5L Eng. Designation: 2GRFE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza LE 6 Cyl 3.5L Eng. Designation: 2GRFE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza AWD 4 Cyl 2.7L Eng. Designation: 1AR-FE, FI, Naturally Aspirated, GAS
  • 2013 Toyota Venza Base 6 Cyl 3.5L Eng. Designation: 2GRFE, FI, Naturally Aspirated, GAS
Product Details
Location : Before Catalytic ConverterNotes : Air/Fuel sensorType : 4-wireQuantity Sold : Sold IndividuallyProduct Fit : Direct FitWire Length : 16.73 in. Wire LengthWarranty : 90-day Walker Products limited warrantyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Series : Walker Products Aftermarket Base Sensor
Before Catalytic Converter Oxygen Sensor, Sold individually, 4-wire, 6 Cyl 3.5L, Walker Products Original Equipment Base Sensor - Before Catalytic Converter
Part Number: WKP25054084
Guaranteed to Fit
$154.49
Vehicle Fitment
  • 2013 Toyota Venza XLE 6 Cyl 3.5L
  • 2013 Toyota Venza XLE 4 Cyl 2.7L B1S1
  • 2013 Toyota Venza LE 4 Cyl 2.7L B1S1
  • 2013 Toyota Venza Limited 6 Cyl 3.5L
  • 2013 Toyota Venza Base 4 Cyl 2.7L B1S1
  • 2013 Toyota Venza AWD 6 Cyl 3.5L
  • 2013 Toyota Venza LE 6 Cyl 3.5L
  • 2013 Toyota Venza AWD 4 Cyl 2.7L B1S1
  • 2013 Toyota Venza Base 6 Cyl 3.5L
Product Details
Location : Before Catalytic ConverterNotes : Air/Fuel sensorType : 4-wireQuantity Sold : Sold IndividuallyProduct Fit : Direct FitWire Length : 16.73 in. Wire LengthInterchange Part Number : DL96090006Warranty : 90-day Walker Products limited warrantyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Series : Walker Products Original Equipment Base Sensor
Driver Side, After Catalytic Converter Oxygen Sensor, Sold Individually, 4-wire, 3.5L 6Cyl - Driver Side, After Catalytic Converter
Part Number: NP2344260
Guaranteed to Fit
$61.99
Vehicle Fitment
  • 2013 Toyota Venza XLE 6 Cyl 3.5L
  • 2013 Toyota Venza Limited 6 Cyl 3.5L
  • 2013 Toyota Venza AWD 6 Cyl 3.5L
  • 2013 Toyota Venza LE 6 Cyl 3.5L
  • 2013 Toyota Venza Base 6 Cyl 3.5L
Product Details
Location : Driver Side, After Catalytic ConverterType : 4-wireQuantity Sold : Sold IndividuallyProduct Fit : Direct FitInterchange Part Number : 13441Warranty : 1-year Denso limited WarrantyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

After Catalytic Converter, Passenger Side Oxygen Sensor, O.E. Quality Universal Replacement Sensor, Sold Individually, 4-wire, 6 Cyl 3.5L - After Catalytic Converter, Passenger Side
Part Number: NP2344209
Guaranteed to Fit
$51.99
Vehicle Fitment
  • 2013 Toyota Venza Limited 6 Cyl 3.5L O.E. Quality Universal Replacement Sensor
  • 2013 Toyota Venza LE 6 Cyl 3.5L O.E. Quality Universal Replacement Sensor
  • 2013 Toyota Venza AWD 6 Cyl 3.5L O.E. Quality Universal Replacement Sensor
  • 2013 Toyota Venza XLE 6 Cyl 3.5L O.E. Quality Universal Replacement Sensor
  • 2013 Toyota Venza Base 6 Cyl 3.5L O.E. Quality Universal Replacement Sensor
Product Details
Location : After Catalytic Converter, Passenger SideNotes : 0.71 in. Thread Diameter; Heated Sensor; Universal FitType : 4-wireQuantity Sold : Sold IndividuallyProduct Fit : Direct FitWire Length : 11.77 in. Wire LengthMounting Style : Threaded-in Mounting StyleReplaces OE Number : 12559850, 12570149, 88975496, 8946502110, 8946502190, 8946513030, 8946548170, 8946548180, 8946706070, 8946706110, 8946712010, 8946748050, MD183145, MD184939, MD185334, MR985103Interchange Part Number : 2344065Warranty : 1-year Denso limited WarrantyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Oxygen Sensor, Sold Individually, 4-wire, OE Replacement Series
Part Number: BS18081
Guaranteed to Fit
$189.49
Vehicle Fitment
  • 2013 Toyota Venza XLE 6 Cyl 3.5L OE sensor technology
  • 2013 Toyota Venza XLE 4 Cyl 2.7L OE sensor technology
  • 2013 Toyota Venza LE 4 Cyl 2.7L OE sensor technology
  • 2013 Toyota Venza Limited 6 Cyl 3.5L OE sensor technology
  • 2013 Toyota Venza Base 4 Cyl 2.7L OE sensor technology
  • 2013 Toyota Venza AWD 6 Cyl 3.5L OE sensor technology
  • 2013 Toyota Venza LE 6 Cyl 3.5L OE sensor technology
  • 2013 Toyota Venza AWD 4 Cyl 2.7L OE sensor technology
  • 2013 Toyota Venza Base 6 Cyl 3.5L OE sensor technology
Product Details
Location : Before Catalytic ConverterNotes : Wideband Heated Sensor TypeType : 4-wireQuantity Sold : Sold IndividuallyProduct Fit : Direct FitWire Length : 17.72 in.Mounting Style : Threaded-in Mounting StyleHex Size : 22 mm Hex SizeConnector Gender : Male ConnectorWarranty : 1-year Bosch limited warrantyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Promotions : CarParts EuroEcomm Landing Page : EuroSeries : OE Replacement Series
Page 1 of 3 | Showing 1 - 15 of 44 results

Popular Products

Helpful Automotive Resources

P2187 Code: System too Lean at Idle (Bank 1)
P2187 Code: System too Lean at Idle (Bank 1)Note that there is only one bank if your car has a straight engine and the scan tool will always refer to that bank as “Bank 1.” P2187 code indicates that your vehicle’s computer detected a potential issue with the fuel mixture at idle.
P2270 Code: O2 Sensor Signal Biased / Stuck Lean (Bank 1, Sensor 2)
P2270 Code: O2 Sensor Signal Biased / Stuck Lean (Bank 1, Sensor 2)Bank 1 is where the #1 spark plug is. O2 sensor 1/1 is the upstream sensor on Bank 1 (different for a Ford than for a Chevy or a Dodge), and O2 sensor 1/2 is the downstream sensor on Bank 1. O2 2/1 is upstream on Bank 2 and O2
P0141 Code: Oxygen Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)
P0141 Code: Oxygen Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)With that in mind, it’s important to note that Bank 1 is always where the number 1 cylinder is located. Thus, on Ford pickups, Bank 1 is the passenger side bank, but on Chevy and Dodge pickups, Bank 1 is the driver side bank. You need to know this, or
P0042 Code: HO2S Heater Control Circuit Bank 1 Sensor 3
P0042 Code: HO2S Heater Control Circuit Bank 1 Sensor 3Bank 1 is the side of the engine where the #1 cylinder is located. P0042 code is set when your car’s PCM determines a potential problem with the heater element circuit of the oxygen sensor.
P0135 Code: Heated O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)
P0135 Code: Heated O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)Diagnostic trouble code (DTC) P0135 stands for “Oxygen O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1).” It is set when the car’s primary computer—also called the powertrain control module or PCM—determines that the heated oxygen sensor (HO2S) 1 heater current is higher or lower than the ideal amp for
P0134: O2 Sensor Circuit No Activity Detected (Bank 1, Sensor 1)
P0134: O2 Sensor Circuit No Activity Detected (Bank 1, Sensor 1)The Bank 1 portion of the code refers to the side of the engine with the number one cylinder. Sensor 1 refers to the upstream O2 sensor.