VW / Audi 4-Pin 2.8/3.5mm Oxygen Sensor Waterproof Connector – OEM 1J0973724A / 1J0973824A
Direct OEM-specification replacement for the Tyco / TE Connectivity 4-pin waterproof wire harness connector used on oxygen (lambda) sensors across Volkswagen and Audi platforms. Cross-references VW / Audi OEM part numbers 1J0973724A and 1J0973824A (also written as 1J0 973 724 A and 1J0 973 824 A). Uses the 2.8/3.5mm contact series in brown nylon housing with waterproof sealing — the standard 4-pin oxygen sensor connector on VW Group vehicles using the MQB and PQ platform architectures.
The 4-pin oxygen sensor connector on VW and Audi vehicles is located in the exhaust system heat zone, where thermal cycling causes the rubber seal to harden and crack, allowing moisture to corrode the terminals. A failed connector produces P0130–P0167 (O2 sensor circuit) fault codes, causing the engine to run rich or lean, increasing fuel consumption, and potentially damaging the catalytic converter. The brown 4-pin connector is also used on the wideband lambda sensor (LSU 4.9) on VW Group vehicles with direct injection engines.
| OEM Number | Type | Application |
|---|---|---|
| 1J0973724A | Female (socket) housing | VW/Audi 4-pin O2 sensor connector — harness side |
| 1J0973824A | Male (plug) housing | VW/Audi 4-pin O2 sensor connector — sensor side |
| Pin | Function | Failure Symptom if Open |
|---|---|---|
| 1 | Heater power supply (12V) | O2 sensor heater fault, P0135/P0141 |
| 2 | Heater ground | Sensor slow to reach operating temperature |
| 3 | O2 signal output (Nernst cell) | P0130–P0167, rich/lean fault |
| 4 | Reference ground / Vs signal | Wideband sensor fault (LSU 4.9) |
| Attribute | Detail |
|---|---|
| Pin Count | 4-Pin |
| Contact Series | 2.8/3.5mm pitch (Tyco/TE series) |
| Housing Material | Nylon, brown |
| Sealing | Waterproof |
| OEM Part Numbers | 1J0973724A / 1J0973824A |
| Applications | Oxygen / lambda sensor, wideband O2 sensor (LSU 4.9) |
| Compatible Models | VW Golf / Passat / Tiguan / Polo; Audi A3 / A4 / A6 / Q5 |
| Terminal Included | Yes |
Q: My VW Golf has a P0135 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 (upstream O2 sensor heater circuit) on VW Group vehicles. Test the O2 sensor heater resistance first (typically 5–20Ω) — if it is within specification, the fault is in the connector (OEM 1J0973724A) or wiring.
Q: Are terminals included?
A: Yes, terminals are included with all variants.
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