6.7 Powerstroke Diesel Has A P21BO Trouble Code

13th Nov 2018

Q. What is a reductant level sensor C high code p21bo. On an 2011 Ford F-350 mean? - Pat

A. The sensor in the DEF system has most likely failed or possibly needs cleaned.  I would do the diagnostics for the sensor to check for proper operation and then replace if it fails.