17056/P0672/001650 - Cylinder 2 Glow Plug Circuit (Q11): Electrical Fault
Possible Symptoms
No Pre-Glow Period
Poor Cold Starting
Possible Causes
Glow Plug Wiring faulty
Glow Plug faulty
Possible Solutions
Check Glow Plug Wiring
Check Glow Plug
This is usually a glow plug, sometimes the glow plug harness. When I got this code I replaced all the glow plugs and the code has not come back. I know it identifies just one plug, but if one has failed the others are not usually far behind.
The glow plug harness is like a spark plug harness with high-current contacts up inside long rubber hoods. They can sometimes get loose or corroded, so inspect and if any are loose, squeeze to tighten them up before reconnecting to the plug.
16705/P0321/000801 - Engine Speed Sensor (G28): Implausible Signal
Possible Symptoms
Engine shuts off
Engine doesn't start
Speedometer inoperative
Glow Plug Indicator Lamp (K29) flashes
Possible Causes
Engine Speed Sensor (G28) loose
Engine Speed Sensor (G28) faulty
Possible Solutions
Check Engine Speed Sensor (G28)
Special Notes
The Engine Speed Sensor (G28) is also used as a reference sensor for the crankshaft position and correlates with the Camshaft Position Sensor Bank 1 (G40) and Camshaft Position Sensor Bank 2 (G163).
When an engine will not start due to mechanical timing or spark/fuel related issues it is not uncommon to set G28/G40/G163 fault codes. The basics should be checked if this code returns after extended craning and a no-start with a new sensor installed.
The engine speed sensor, aka the crank sensor, will prevent engine starting if it fails. It sits down on the front of the crankcase, by the oil filter.