What is Valve N373?
The valve N373 is an electro-hydraulic solenoid valve that regulates oil pressure inside the clutch of a Haldex clutch. It controls rear-axle engagement and torque distribution in all-wheel-drive vehicles under the brands of Volkswagen, Audi, Škoda, SEAT and others using Haldex AWD.
🚨 Typical Symptoms of a Faulty N373 Valve
- Loss of AWD / rear-axle engagement — the car behaves like a front-wheel-drive. Especially noticeable under load, acceleration or on slippery surfaces.
- No pressure build-up in clutch during pump activation — diagnostics show pump running, but measured clutch pressure stays low or zero, despite attempts to engage AWD via scan tools.
- Stored error code 02248 — described as “Valve for Controlling Clutch Operating Pressure (N373)”, possibly with sub-descriptions like electrical fault, mechanical fault, open or short circuit.
- AWD intermittently works then fails — sometimes AWD engages, sometimes not, especially after clearing codes or after service.
🔍 Why Does N373 Fail?
| Cause | How it leads to failure |
|---|---|
| Old / contaminated Haldex oil | Metal particles and sludge can block or jam the valve, preventing proper pressure regulation. |
| Coil / electrical failure | The solenoid may lose proper resistance (open circuit or short), so the valve cannot operate. |
| Mechanical sticking or wear | Valve may be stuck due to contamination or degraded seals — even if electrical coil is fine. |
| Incorrect maintenance (wrong oil/filter/service intervals) | Skipping oil/filter change, or using wrong fluid, accelerates wear and clogging. |
🛠️ How to Diagnose a Faulty N373 Valve
- Use diagnostic tool (VCDS / ODIS)
- Monitor clutch pressure during pump activation — if pressure remains ≈ 0 bar, valve likely faulty.
- Apply 12 volts to the valve and check if it clicks (moves).
- Perform “Output Test” (pump + valve activation)
- If pump runs but clutch pressure does not build → indicates valve failure (mechanical or electrical).
- Measure valve coil resistance (if technically possible)
- Typical resistance ~ 5–8Ω .
- Open-circuit (very high resistance) or short (very low) → valve coil is faulty.
- Normal resistance but no pressure → likely mechanical sticking.
- Inspect oil/filter for contamination
- Dirty oil or full of metal particles usually signals valve contamination or wear.
✅ When to Replace vs. When to Try Cleaning
1.Replace valve if:
- Error 02248 returns immediately after clearing,
- Coil resistance is out of spec or shorted / open,
- Pressure stays zero despite pump running,
- AWD still does not engage after fluid/filter service.
2.Try cleaning valve only if:
- Coil resistance is OK,
- Oil & filter are filthy (indicating contamination),
- It seems like sticking due to sludge rather than electrical failure — cleaning + new seals may restore function.
🧼 Preventive Maintenance to Extend N373 Life
- Change Haldex fluid every ~30,000 km (or per manufacturer’s recommendation).
- Replace the filter at service intervals.
- Always use correct, OEM-spec Haldex oil.
- At first signs of slipping / loss of AWD / hesitation — don’t ignore
✅ Can I buy a Haldex N373 valve from you?
Yes, we have tested valves with a 12month warranty available.
Link: For 2nd/3rd generation Haldex.
Link: For 4th generation Haldex.