I replaced the torque sensor, but the heavy steering and the EPS error on the meter still won’t go away. When I checked the power steering EPS unit, this is what I found. The IC is melted.
With the PCB in this condition, there’s no point trying to fix anything else, so I consulted with a circuit board repair specialist. S2000 EPS failures are apparently common, so the specialist keeps repaired units in stock. Their process is: defective unit arrives → identify the problem → send a repaired unit from inventory.
They sent me two EPS units. Apparently there are compatibility issues, and even the repaired units may or may not work, so they suggested I try both. I connected the first EPS unit they sent, and the moment I turned on the engine, the EPS error on the meter disappeared and the power steering was restored. The second EPS unit, however, still has the error light lit, and even after resetting the EPS, the heavy steering and error display won’t change at all.
Looking at the parts catalog, there are five different EPS units for the S2000, each with different part numbers depending on the model year. Online information isn’t clear about whether later model parts are compatible with earlier models, but factually speaking, there’s definitely a relationship between vehicle model year and the corresponding EPS unit. If you don’t understand this aspect before attempting repairs, you end up in a probability-based repair situation: replacing the torque sensor, replacing the steering gearbox, purchasing multiple EPS units, and hoping one of them is compatible with your vehicle type and has no PCB defects. This complexity might explain why there’s so much vague information about S2000 repairs online. My own repair might not have even needed the torque sensor replacement. And even if I had an EPS unit with a functioning PCB, if it wasn’t compatible with my vehicle, the problem wouldn’t be solved. So buying a used EPS unit on Yahoo Auctions isn’t necessarily a fix either.
With the heavy steering issue resolved, I adjusted the steering alignment. Changed from toe-in 0 to 40 minutes out on both sides. The steering is now perfectly centered, and the EPS repair is complete.
