4-Pin 7282-7040-10 Yazaki Waterproof O2 Sensor Male Connector – Toyota Rear O2 Sensor & AC Assembly

Direct-fit replacement for Yazaki OEM part number 7282-7040-10, the 4-pin waterproof male plug connector used for rear (downstream) oxygen sensor harness connections and AC assembly wiring on Toyota vehicles. The 7282-7040-10 is the male plug (harness side); the mating female socket on the sensor is 7283-7040-10.

Key Specifications

• OEM Part Number: 7282-7040-10 (male plug)
• Mating Female: 7283-7040-10
• Pin Count: 4
• Gender: Male plug (with wire)
• Series: Yazaki 090 waterproof series
• Wire Gauge: 18 AWG (0.5 mm²)
• Wire Length: 5.5 inches (140 mm)
• Waterproof Rating: IP68
• Housing Material: PA66 glass-filled nylon
• Terminal Material: Copper alloy, tin-plated
• Current Rating: Up to 10A per pin

Applications

• Toyota rear O2 sensor (downstream): Bank 1 Sensor 2 and Bank 2 Sensor 2 harness connectors on Toyota 2.4L, 3.0L, 3.5L V6 engines
• AC assembly wiring: Compressor clutch and pressure sensor harness on Toyota HVAC systems
• Lexus shared platform: IS250, IS350, ES350 downstream O2 sensor harness

Rear O2 Sensor – Why It Matters

The downstream (rear) O2 sensor monitors catalytic converter efficiency. A failed connector at this location causes:

• P0136 / P0156 – O2 Sensor Circuit (Bank 1/2, Sensor 2)
• P0420 / P0430 – Catalyst System Efficiency Below Threshold – often triggered by a faulty downstream O2 connector, not a failed catalytic converter
• Failed emissions test – ECM cannot confirm catalyst efficiency without downstream O2 signal

Frequently Asked Questions

Q: Can a bad downstream O2 connector cause a P0420 cat code?
A: Yes. P0420 (Catalyst System Efficiency Below Threshold) is triggered when the downstream O2 signal does not show the expected flat waveform after the catalyst. A corroded 7282-7040-10 connector causes signal dropout, which the ECM interprets as catalyst failure. Always inspect the connector before replacing the catalytic converter.

Q: What is the difference between 7282-7040-10 and 7283-7040-10?
A: 7282-7040-10 is the male plug (harness side); 7283-7040-10 is the female socket (sensor side). In the Yazaki 7282/7283 series, 7282 always denotes the male plug and 7283 always denotes the female socket.

Q: What crimping tool is needed?
A: Use a ratchet crimper for 0.5mm² (18 AWG) Yazaki 090 terminals – Hozan P-706 or Engineer PA-09.

Package Contents

1 × 4-Pin Male Connector (7282-7040-10) with 18 AWG wire and terminal insert