Hello again everyone, some have you may have seen my previous posts about preparing my 1998 car for German inspection. This is my last major issue. I've had the car 6 years but from almost the beginning it would give me the "service vehicle soon" caution on the DTC. For code C1281. Which as I understand it is the code saying the Steering Wheel Position Sensor is bad. Seemed like this happened about 50% of the time I drive the car. I've had the car aligned twice as well since this issue appeared.

Well poor decision making on my part but since my car does not have Active Handling and the used sensors were over 1000 dollars when I looked, I decided to live with it since it seemed to have no detrimental effect on the car.

However, with my pending move I need to get that code fixed lest the "service vehicle soon" appear while the German inspectors are clearing my car through customs. So while i was having my leaking crankshaft oil seal and harmonic balancer replaced (precautionary) I asked a the corvette shop in Little Rock to check out my SWPS to finally get the answer if it was bad. The kicker is that they said all the voltage swings as they moved the wheel were correct. Now I'm stumped. Is it my EBCM that has gone bad or is it something else? Like I said no AH so it really has no effect on driving the car, but I need it fixed and I'm not sure where to go from here.

TLDR: I get C1281 but supposedly the voltage on my SWPS is correct, now what do I do? Thanks for the help.

 

It is possible that it is a bad wheel sensor. Check the history for any of these:
DTC C1221 LF Wheel Speed Sensor
DTC C1222 RF Wheel Speed Sensor
DTC C1223 LR Wheel Speed Sensor
DTC C1224 RR Wheel Speed Sensor

 

Ok, I had not heard of that causing the SVS message, currently the only ebcm code I have is that C1281. Is there any other way to tell if the wheel speed sensor is bad? Where exactly are those sensors located?

Thank you for the suggestion.

 

They are on the back of each hub. Each has a 2 wire connector. I just remember when my mechanic's helper accidentally disconnected one, the car threw all kinds of codes. We ended up replacing the SPS before figuring out what the real culprit was. Do you have any history codes or just the 1281?

 

Ok I'll have to check those. Currently no just, the 1281 H, but it comes back to C. I have seen other codes here and there but nothing currently.
the 1281 is the consistent one. However, I did get a ABS light one morning about 3 weeks ago on my first time driving the car in 4 months, when I hit a pot hole on the way to work. Did the research on it and I believe it was right front wheel sensor. I decided to reset and see if it would come back. In the 6 years I've had the car that's the only time that's ever happened, even though the I've gotten 1281 on/off for awhile. But I think you may be on to something.

 

I am in the same boat, I cleared and fixed a few codes (air pump) etc.. they have all stayed away but the 1281. The odd part is i clear it and when it comes back it READ H for history? it should be C for current in my Opinion. SO you mention pothole. I have been chasing mine for a few weeks reading everything. One thing that might help you, i have read you can have Ground issues that will throw odd codes. MAYBE this might be part of it. I think you will get more odd codes not the same one over, but i mention it, who knows. I will be watching your thread to see if you solve and will let you know if i find anything on mine. My car only has 20,000 so i wouldn't think the sensor is bad, but I did replace a front wheel bearing just a few weeks ago (which also shouldn't have failed already i guess).

 

The SWPS is actually two sensors in one. A Tech2 is needed to read the digital signal and the analog signal. Those two signals then have be compared to determine if the sensor is good.

W/O JL4
"Conditions for Setting the DTC

DTC C1281 will set when the digitally derived centered angle differs from the analog derived angle by 27 degrees or more for a period of 5 seconds.
DTC C1281 will set if the index pulse is not seen between ± 37 degrees or is seen between -185 degrees and -37 degrees or 37 degrees and 185 degrees of steering wheel travel.
DTC C1281 will set if phase A and or phase B are shorted."

The troubleshooting procedure gets very involved but cleaning the grounds for the EBTCM and Checking for poor connections would be a good start.
"An intermittent malfunction is most likely caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation. Refer to Testing for Electrical Intermittents in Wiring Systems."

 

I'm chasing ABS sensor issues on my 4runner - check them with an ohm meter - if they are a dead short they are probably bad....

 

UPDATE: So I replaced my AC blower 2 weeks ago and when doing so I unplugged the battery. When I powered the car back up C1255 was present. This was the day before I scheduled to drop the car off with chevy to see if they could test the system. With code C1255 present they told me the only thing to do was to replace the EBCM. Unfortunately this meant I need to go on a parts hunt. I ended up finding a used one that had the same part number. With that replaced the code has not returned and I've been driving the car daily for about a week and a half.

 

Alright so no sooner did I post that update I ended up Jinxing myself. C1281 came back today without any other messages. It seems to happen when I back out of my drive way. I'll have the steering wheel fairly hard to the left in order to get out without scrapping. As the front passenger side wheel steps down out of my driveway and onto the street it seems to trigger it. Not all the time but it seems to be the most common occurrence. Sucks to be out a working EBCM and 1500 bucks labor and parts.

Anyone have any idea which grounds it could be? The ones from the diagram on the drivers side frame rail all showed no signs of corrosion.

 

Judging from your description, perhaps the shop that gave the SWPS a clean bill of health needs to take a second look. Maybe you can take a good look at the connections and wiring for the SWPS.

Here is a link to ground locations.
https://www.corvetteforum.com/forums...locations.html

Here is the troubleshooting procedure from the manual.