Error Code P121

[TMax]

Does anyone know what this error code means? I am experiencing problems with my brake lights and now my speedometer. Pulled this code off with the Smarty but it did not give me an explanation. Showed "Unknown Code"

Might be P0121?

 

[JLandry]

There is a P0121 trouble code associated with gasoline engines, but not for a diesel engine.



P0121 = Throttle Position Sensor Voltage Does Not Agree with MAP Sensor.



This is a rationality check of the throttle position against manifold vacuum.



Could it be P2121 instead?



Either one would have nothing to do with brake lights or the speedometer.



Drive safe,



John L.

 

[TMax]

Thanks John. I'll have to look again on my Smarty. This is all too weird. Damn electronics!

 

[macdaddy]

P0121.....

Mine had this numerous. it's benign. It's "Common Rail Pressure Sencer Performance". You need to get the necessary reflash. If you dont and simply clear it with out the reflash it was just keep coming back.



Mac