Dsc/tcs dtc c1937 - RX8Club.com

04-28-2010, 02:15 PM

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willylee

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Dsc/tcs dtc c1937

I bought a used 2005 road racer last year. I spent the Winter sorting through problems and things are starting to look up. One issue I'm still struggling with involves the DSC/TCS. In a way it's a moot point since I typically turn it off by holding in the DSC button, forcing a system error, before going out on track. Even without DSC the car is impressively stable. Potential spins are easy to catch and it exhibits nice flat, four wheel drifts. So,the DSC/TCS system might seem unneccessary, but then again, it might be a benefit in the rain. The ABS system seems to work fine and is a real plus, it being legal in my class.
When I drive the car a short distance with the DSC enabled, I get the C1937 (Steering Wheel Sensor Offset Failure) code. Originally, the computer had been throwing a bevy of steering angle sensor codes. The steering wheel angle sensor had been damaged by the previous owner when he installed a quick-release wheel. After I replaced the sensor, the sole remaining fault was C1937.
This is my theory: When you initialize the sensor (turning the wheel from lock to lock) the computer counts the pulses and divides by two to determine a theoretical zero (straight ahead). My guess is that the physical mechanism of the steering rack is not centered so that steering rack zero and sensor zero do not agree. The driver sees the car tracking straight down the road, but the computer sees the car going in circles and makes the decision that the system has failed, disables it and issues the C1937 code. When I set my front wheels straight and counted the turns center-right to lock and center-left to lock, I expected to find a large difference. I found a small difference, perhaps 10 degrees. Now I'm not so sure about my theory. I know there must be some allowable error band, but how small is it? I thought I might fiddle with the tie-rod ends and try to get the best rack zero I can to see if I can get the rack and the sensor in synch.
Any comments? I guess I'm just looking for someone to tell me I'm moving in the right direction or someone to tell me I'm completely full of ca-ca and don't know what's going on.

Thanks.

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