DTC 56, Injection Pump Calibration Resistor Error: Notes

PCM uses a calibrated resistor mounted internally in injection pump to determine fuel rates. Resistor value is stored in PCM memory. If PCM memory has been disturbed or PCM has been replaced, PCM will relearn resistor value on next ignition cycle.

DTC 56 will set when PCM has lost its memory and is unable to read a resistor value on the next ignition cycle. Possible poor performance problem. PCM will light MIL and a current and history DTC 56 will set. PCM will default to the lowest fuel table.

NOTE: Test numbers refer to numbers on diagnostic chart.

This step determines if a problem exists with fuel solenoid driver connection or if injection pump is faulty.