Toyota 4-Pin 2.2mm Fog Light / Front Oxygen Sensor Waterproof Connector – OEM 6188-0217 / 6189-0372 / 6188-0327
Direct OEM-specification replacement for the Sumitomo 4-pin waterproof wire harness connector used on fog lights and front (upstream) oxygen sensors across Toyota platforms. Cross-references Sumitomo / Toyota OEM part numbers 6188-0217, 6189-0372, and 6188-0327. Uses the 2.2mm contact series in grey nylon housing with waterproof sealing — the standard 4-pin sensor and lighting connector on Toyota’s 1JZ, 2JZ, 3S-GTE, 1NZ, 2NZ, and related engine platforms.
The 4-pin 2.2mm connector is used on two critical circuits on Toyota vehicles. As a front oxygen sensor connector, it is located in the exhaust system heat zone upstream of the catalytic converter, where thermal cycling causes the rubber seal to harden and crack, allowing moisture to corrode the terminals. A failed connector produces P0130–P0135 (upstream O2 sensor circuit) fault codes, causing the engine to run on open-loop fuel control — increasing fuel consumption and potentially damaging the catalytic converter. As a fog light connector, a failed connection causes a non-functioning fog light.
| OEM Number | Application |
|---|---|
| 6188-0217 | Sumitomo 4-pin 2.2mm connector (female housing) |
| 6189-0372 | Sumitomo 4-pin 2.2mm connector (alternate) |
| 6188-0327 | Sumitomo 4-pin 2.2mm connector (alternate) |
| Pin | Function | Failure Symptom if Open |
|---|---|---|
| 1 | Heater power supply (12V) | O2 sensor heater fault, P0135 |
| 2 | Heater ground | Sensor slow to reach operating temperature |
| 3 | O2 signal output | P0130–P0132, rich/lean fault |
| 4 | Signal ground / reference | Sensor signal fault |
| Attribute | Detail |
|---|---|
| Pin Count | 4-Pin |
| Contact Series | 2.2mm pitch (Sumitomo series) |
| Housing Material | Nylon, grey |
| Sealing | Waterproof |
| OEM Part Numbers | 6188-0217 / 6189-0372 / 6188-0327 |
| Applications | Front (upstream) oxygen sensor, fog light harness |
| Compatible Models | Toyota Corolla / Camry / RAV4 / Hilux / Land Cruiser / Supra / Celica |
| Terminal Included | Yes |
Q: My Toyota has a P0135 upstream O2 sensor heater fault — could it be the connector?
A: Yes. A corroded or open 4-pin O2 sensor connector is a common cause of P0135 on Toyota vehicles. Test the O2 sensor heater resistance first (typically 5–20Ω) — if it is within specification, the fault is in the connector or wiring.
Q: Are terminals included?
A: Yes, terminals are included with all variants.
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4 Pin Connectors
