[Barry Allen]

I replaced the glow plugs on my 2018 sedan and tested the old glow plugs.

3 glow plugs = 16.4 ohms
1 glow plug = 19.8 ohms

Everything I read online says that a "good" glow plug should show maybe 1-2 ohms resistance and anything higher is going bad. In the tutorials I see on YouTube I frequently see bad glow plugs testing as either totally shorted out (infinite resistance, off the chart on the multimeter) or resistance in the hundreds of ohms.

Does anyone here think the above results show that I have all 4 plugs that are/were bad?

 

[15cruzediesel]

Hard to say without knowing what the manufacturers spec resistance should be. Be interesting to ohm your new ones for comparison.

At some point the car would throw a code for either low or high glow plug circuit resistance.

FYI. A shorted glow plug would be zero resistance. An open glow plug would be infinite resistance.

 

[Barry Allen]

At some point the car would throw a code for either low or high glow plug circuit resistance.

The CEL is perpetually on so I don't know if there was a code. In December, on the coldest day of the winter, it was very rough starting and it motivated me to just change the plugs out this week since they are almost 90,000 miles.