Nissan 4-Pin Oxygen Sensor Connector – OEM 7287-3838-40 / 7286-3838-40 | Sumitomo
Direct OEM-specification replacement for the Nissan 4-pin heated oxygen sensor (HO2S) connector. Cross-references Sumitomo part numbers 7287-3838-40 (female/socket side) and 7286-3838-40 (male/plug side). Used on upstream (pre-cat) and downstream (post-cat) oxygen sensors across Nissan and Infiniti platforms. Available bare or with 15cm pre-wired leads.
| Pin | Function | Failure Symptom if Corroded |
|---|---|---|
| 1 | Heater element power (+12V switched) | P0135 / P0141 — O2 sensor heater circuit malfunction |
| 2 | Heater element ground | Slow O2 sensor warm-up, rich running when cold |
| 3 | O2 signal output to ECU (0–1V) | P0130–P0167 — O2 sensor circuit fault, poor fuel economy |
| 4 | Signal ground / reference | Erratic O2 reading, ECU unable to trim fuel |
| Attribute | Detail |
|---|---|
| Pin Count | 4-Pin |
| OEM Part Numbers | 7287-3838-40 / 7286-3838-40 |
| Connector Series | Sumitomo automotive series |
| Housing Material | High-temp nylon (PA66) |
| Wire Option | Bare connector / 15cm pre-wired leads |
| Application | Heated oxygen sensor (HO2S) harness — upstream and downstream |
| Compatible Brands | Nissan, Infiniti |
| Code | Description |
|---|---|
| P0130 | O2 sensor circuit — Bank 1, Sensor 1 (upstream) |
| P0136 | O2 sensor circuit — Bank 1, Sensor 2 (downstream) |
| P0135 | O2 sensor heater circuit — Bank 1, Sensor 1 |
| P0141 | O2 sensor heater circuit — Bank 1, Sensor 2 |
| P0150 | O2 sensor circuit — Bank 2, Sensor 1 |
Q: My Nissan has P0135 but the O2 sensor heater tests OK — what’s wrong?
A: P0135 is a heater circuit fault — it means the ECU cannot confirm the heater is operating, which can be caused by a corroded Pin 1 (heater power) or Pin 2 (heater ground) in the 4-pin connector. Inspect the connector before replacing the O2 sensor.
Q: Are terminals included?
A: Yes, terminals are included with all variants.
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4 Pin Connectors
