U0320 — Power steering module software mismatch detected

The vehicle's computer found a software conflict with the power steering control module. This usually happens after an update, module replacement, or communication error between control units. It can cause the power steering to behave unpredictably or fail to assist properly.

Common causes

The cause is almost always one of a few things. Here they are — U0320 rarely comes from anything outside this list:

• Recent power steering module software update or flash
• Faulty or incompatible power steering control module installed
• Corrupted communication between control modules
• Wiring or connector issues in the power steering circuit
• Battery voltage problems causing module errors

Where to start

In the order a sensible mechanic would work — the cheap checks first, the expensive replacements only after:

1. Check and clear any recent software updates or flashes
2. Inspect wiring and connectors for damage or corrosion
3. Perform a module reset or reflash with correct software
4. Replace faulty power steering control module if needed
5. Verify battery and charging system health

That is what holds for U0320 in general. From here it depends on your engine — tell me which car it is and what it does, and I will give you the steps for it: real procedures, torque figures and diagrams instead of general advice.