Cummins ISB CM550 (1990-94) Fault Code: 528 PID: 93 SPN: 93 FMI: 2 Alternate (Switched) Torque Curve Switch Circuit

Circuit Description
The torque curve switch circuit allows the operator to select from up to three preprogrammed
torque curves using a two- or three-position switch depending on which curve the original
equipment manufacturer (OEM) has provided.

Component Location
The location of the torque curve switch circuit varies with each OEM and equipment model.
Refer to the OEM manual.

Shop Talk
The switch should be monitored for proper operation in INSITE™. If the switch is changing
state correctly on the service tool, then the problem does not lie in the switch circuit. The
three-position switch has three states:

1) Position 1 – open
2) Position 2 – closed
3) Position 3 – 1500-ohm resistance.

The two-position switch has two states:
1) Position 1 – open
2) Position 2 – closed.