Injection Timing Stepper Motor

Figure 3-18: Stepper Motor Replacement:

Figure 3-19: Injection Timing Stepper Motor Circuit:

Injection Timing Stepper Motor
The stepper motor is used to advance or retard timing of the electronic injection pump. The motor is controlled by the PCM and is actuated by input signals primarily from the coolant, air, and fuel temperature sensors

A stepper motor fault will affect desired and measured injection timing degree readings on the scan tool. A difference of 5° or more between the readings indicates a motor fault.