Toyota prius 3rd gen Air fuel Ratio Sensor (Blank 1 Sensor 1) Assembly (D24)

Toyota Prius 3 ^rd Generation (XW30)

Air fuel Ratio Sensor (Blank 1 Sensor 1) Assembly Wiring Guide: DIY Pinout Diagram

What is: The Air-Fuel Ratio Sensor (Bank 1 Sensor 1) Assembly is a key exhaust component located upstream of the catalytic converter on Bank 1 (the side of the engine with cylinder 1). It measures the precise oxygen concentration in the exhaust gases to determine the air-to-fuel ratio of the engine. The Engine Control Module (ECM) uses this data to adjust fuel injection and ignition timing, ensuring efficient combustion, better fuel economy, and reduced emissions.

Air fuel Ratio Sensor (Blank 1 Sensor 1) Assembly (89467-52060)

Toyota Prius XW30 Air Fuel Ratio Sensor 89467-52060 Bank 1 Sensor 1

OEM Toyota 89467-52060 Air Fuel Ratio Sensor upstream sensor

Genuine Toyota Air Fuel Ratio Sensor 89467-52060 location under hood

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1. Introduction

      The  Toyota Prius 3rd Generation Air-Fuel Ratio Sensor (Bank 1 Sensor 1), also known as the upstream oxygen sensor, is a highly sensitive component installed on the exhaust manifold, before the catalytic converter. Its main function is to accurately measure the amount of oxygen in the exhaust gases and provide real-time feedback to the Engine Control Module (ECM). Unlike conventional oxygen sensors, this wideband sensor offers precise readings across a broad range of air-fuel mixtures, allowing the ECM to make quick and accurate adjustments to the fuel injection and ignition timing. This helps maintain the ideal stoichiometric ratio (14.7:1) for efficient combustion. As a result, the engine achieves better fuel economy, lower emissions, and smoother performance. The sensor plays a vital role in the Prius hybrid system, ensuring both environmental friendliness and optimal engine efficiency by keeping the exhaust system and catalytic converter functioning properly.

Related parts and Accessories

• Exhaust Manifold Assembly – The sensor is mounted on this part to monitor exhaust gases.
• Catalytic Converter (Front / Upstream) – Works with the sensor to reduce harmful emissions.
• Engine Control Module (ECM)– Receives signals from the sensor to adjust air-fuel mixture.
• Sensor Wiring Harness & Connector – Connects the sensor to the ECM for signal transmission.
• Exhaust Pipe Gaskets & Bolts – Ensure proper sealing and connection between exhaust components.
• Heat Shield – Protects the sensor and wiring from excessive exhaust heat.

2. Air fuel Ratio Sensor (Blank 1 Sensor 1) Assembly Wiring Diagram & Pinout

A. Connector Location

• Air fuel Ratio Sensor (Blank 1 Sensor 1) Assembly Mounting Location: Directly on the exhaust manifold (upstream position) — before the catalytic converter.
• Connector Type:
  • D24 (4 pin) Dark Gray housing

B. Wiring Table

Air fuel Ratio Sensor (Blank 1 Sensor 1) Assembly (D24)

D24 TERMINALS OF Air fuel Ratio Sensor (Blank 1 Sensor 1) Assembly CONECTOR

Terminal No	Symbol (Pin Definition)	Wiring (Color Code) & Color	Electrical Paths
D24-1	HA1A	(Y) Yellow	➔ D28 18 (HA1A) [Engine Control Module]
D24-2	+B	(B) Black	➔ ✠ ➔ DA2 4 ➳ 1 2 ➤ 10A Blade Fuse [EFI NO.2]
D24-3	A1A+	(Y) Yellow	➔ D28 103 (A1A+) [Engine Control Module]
D24-4	A1A-	(BR) Brown	➔ D28 126 (A1A-) [Engine Control Module]

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Quick Pin Summary – D24 Connector

4-Pin dark-gray Connector

• D4-1 HA1A (Heater Control) :
  Air-fuel ratio sensor heater control signal sent to the ECM (D28-18) to regulate sensor operating temperature.
• D4-2 +B (Battery Power) :
  Battery power supply for the sensor heater, fed through the EFI NO.2 10A fuse.
• D4-3 A1A+ (Pumping Current +) :
  Pumping current positive signal to the ECM (D28-103) used to calculate precise air-fuel ratio.
• D4-4 A1A− (Pumping Current − / Reference) :
  Pumping current negative (reference) signal to the ECM (D28-126), completing the sensor measurement circuit.

Quick Note: The D24 connector is a 4-pin dark-gray connector for the upstream Air-Fuel Ratio Sensor (Bank 1 Sensor 1); it includes heater power and control circuits (+B, HA1A) and pumping current signal circuits (A1A+, A1A−) that communicate directly with the ECM for precise air-fuel ratio control.

3. DTC Error Codes Related to Bank-1 Sensor-1

Applies to the upstream Air-Fuel Ratio (A/F) sensor mounted on the exhaust manifold (Bank-1, Sensor-1).

DTC Code	Description	Trouble Area
P0031	Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)	Open in air fuel ratio sensor (sensor 1) heater circuit Air fuel ratio sensor heater (sensor 1) ECM
P0032	Oxygen (A/F) Sensor Heater Control Circuit High (Bank 1 Sensor 1)	Short in air fuel ratio sensor (sensor 1) heater circuit Air fuel ratio sensor heater (sensor 1) ECM
P2195	Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1)	Open or short in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (sensor 1) Air fuel ratio sensor (sensor 1) heater Intake system Fuel pressure Fuel injector assembly EGR valve assembly ECM
P2196	Oxygen (A/F) Sensor Signal Stuck Rich (Bank 1 Sensor 1)	Open or short in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (sensor 1) Air fuel ratio sensor (sensor 1) heater Intake system Fuel pressure Fuel injector assembly EGR valve assembly ECM
P2237	Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 1 Sensor 1)	Open in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (sensor 1) ECM
P2238	Oxygen (A/F) Sensor Pumping Current Circuit Low (Bank 1 Sensor 1)	Open in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (sensor 1) ECM
P2239	Oxygen (A/F) Sensor Pumping Current Circuit High (Bank 1 Sensor 1)	Open in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (sensor 1) ECM
P2252	Oxygen (A/F) Sensor Reference Ground Circuit Low (Bank 1 Sensor 1)	Open in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (sensor 1) ECM
P2253	Oxygen (A/F) Sensor Reference Ground Circuit High (Bank 1 Sensor 1)	Open in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (sensor 1) ECM

Tech Tip: Always fix air/exhaust leaks, MAF contamination, and fuel pressure issues before condemning the A/F sensor. Clear codes and perform a drive cycle to confirm repair.

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