DTC 17, High Resolution Circuit Fault: Notes
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1995 GMC Yukon, 1995 GMC Suburban, 1995 GMC Pickup, 1995 GMC Cab & Chassis, and 1995 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
Optical sensor provides a high resolution signal to PCM by counting pulses on sensor disk located in injection pump. High resolution signal is one of the most important inputs used by PCM for fuel control and timing. DTC 17 will set when 8 pump cam reference pulses occur without an increase in high resolution counts (internal to PCM). PCM will default to backup fuel.
NOTE:
Test numbers refer to numbers on diagnostic chart.
- This step determines if a 5-volt reference is present.
- This step checks ground circuit.
- This step checks if sensor is sending a signal back to PCM.