Diesel Cold Advance System Check: Notes

With ignition on and coolant temperature below 80°F (27°C), the ECM grounds circuit No. 905 to the cold advance relay. Grounding circuit No. 905 turns on cold advance relay, to supply 12 volts to the cold advance solenoid (in the injection pump), and glow plug controller. The cold advance solenoid is now energized, which causes injection pump timing to be advanced about 4 degrees.