Speed Sensor - Signal Implausible #4201/4206; Oxy Sensor P1125

[latestart]

Hi:

I have a MY99 996 C2 Coupe

I got the dreaded seat sensor error 46 a few weeks ago, so I thought I would start the process by clearing the code. While I was there, I checked for other errors and encountered speed sensor errors that I didn't anticipate/understand.

The only contributing factors I can imagine are:

> Tires replaces a few thousand miles ago. Don't know if they ran the car on a machine (but I doubt it)

> California SMOG test a few weeks ago -- I know for sure they run the rear wheels (only) on a treadmill-type device.

Is it possible that the smog test triggered the error by running the rear wheels while the front wheels were immobilized?

I also have error P1125 -- Oxygen sensing range 1 Cylinder (4-6).

The car runs fine, I have just under 45k miles. I have put on approx 20k miles in the past 18 months. 90% highway miles in a 60 mile a day round trip commute. I saved all of the information and cleared all the codes so I can check in a week and see if they re-occur.

Any thoughts and feedback are welcome.

Thanks in advance!

John

[Loren]

Do you mean airbag fault code 46 or alarm fault code 46?

Neither one is related to the ABS sensors. Airbag fault code 46 is the drivers seat belt buckle.

If the P1125 reoccurs then try cleaning the MAF.

[RFM]

The car trigger a fault code if the rear or front wheels are activated separately during a certain time and speed.

[Tool Pants]

After my last smog inspection I had 2 speed sensor faults.

I thought it was because when the inspector backed the car off the rollers he spun the rear tires while the front tires were not moving. But now that I think about it must be due to the simple fact only the rear wheels were spinning during the test.

[latestart]

To clarify the post above:

• Code #46 with the airbag light on the dash is the problem I had. I reset the light and it has not come back in 1day/60 miles of driving. We'll see what happens....
  
• Agree on the speed sensor -- probably the SMOG test
  
• Driving the car this week, will see what happens with the MAF-related code
  

Thanks for the feedback, this board is really helpful.

Cheers,

John

[Loren]

To clarify the post above:

• Code #46 with the airbag light on the dash is the problem I had. I reset the light and it has not come back in 1day/60 miles of driving. We'll see what happens....
  
• Agree on the speed sensor -- probably the SMOG test
  
• Driving the car this week, will see what happens with the MAF-related code
  

Thanks for the feedback, this board is really helpful.

Cheers,

John

Airbag fault code 46 is the drivers seat belt buckle.