The crank position sensor may be indicating a problem. A proper scan tool will give an indication of how old the code is.I'm having a fairly regular, but totally intermittent CEL these days. I had the codes read at the parts store and they come back as: glow plug 3, glowplug 4, and Crank Position Sensor. The van has not misfired or failed to start/run.
Replace all three and see what happens?