Steering Angle Sensor / Spiral Cable design and construction

Does anybody have any info on the construction of the Spiral cable and Steering Sensor assembly? In the process of replacing the headlight stalk, the cover plate popped off the spiral cable housing, and part of the flex (spiral) cable came out of the assembly. I was able to get the flex cable back into the assembly, but I now have a C1231 error code for the angle sensor (the ONLY code present), and I am getting an angle position readback of -850.5 degrees (which I would imagine corresponds to an angle of 2.4 turns one direction - fully one way - not sure which way...). I tried clearing the code and recalibrating, but the code and wrong angle reading remains. (I have also verified the voltage and ground readings at the connector, per the TIS repair manual.)

I am fairly confident that the sensor itself wasn't damaged, since even when the cover popped off, and all during the reassembly, it was handled extremely gently; but I'm thinking I may not have wrapped the spiral cable correctly, or put the assembly back together quite right. (It sounds and feels fine - no binding or rubbing noises, etc.)

Does anyone one have or have links to details on the construction of this specific angle sensor and spiral cable assembly, or know someone who might? I really don't feel like replacing this assembly ($$$), especially since I don't think it's damaged - I think I somehow just put back together incorrectly or somehow didn't align something having to do with the angle sensor. And obviously the dealership is not going to try to re-assemble it, so the "default" in the repair manual is to replace it. There has to be a way to correctly reassemble it.

 

Any contacts from Toyota that could provide some guidance?

 

Thanks very much for your reply, Paul!

The headlight stalk was replaced to add Auto headlight and Fog light switch functionality, which works fine.

The only code present through Techstream is C1231. I followed the Repair Manual for that code and verified the DOME and ECU-IG voltages, as well as the ground connection. All were fine. The angle position readback in Techstream, though, reads -850 degrees and does not change with any turn of the steering wheel. All other functionality, including the switches on the steering wheel for audio control, etc., work fine. The only indication at all of any problem is the skid indicator in the display (and the presence of the C1231 code).

I'm still just thinking that somehow I put things back together incorrectly.

What's the relationship (if any) between the spiral cable (the flex cable) and the angle sensor? Does the angle sensor read its value somehow from the position/rotation of the flex cable itself? I'm not sure that the flex cable got routed around the small rollers inside the assembly the way it was before it came out. But again, it only came out a few inches, and I had hoped that I slipped it back in correctly - but obviously something changed.

A key to me is that the readback says -850.5 degrees, which is basically approximately 2.4 turns one direction - so it seems like the angle sensor is maxed out in one direction, and whatever makes it change isn't engaged or positioned for the sensor to read it.

They don't use "clocksprings" anymore, do they? I mean, is there a physical spring that is used in the angle sensor? What does it use for position reading?

Questions, questions....