Cummins ISB CM850 (2003-06) Fault Code: 689 PID: 190 SPN: 190 FMI: 2 Engine Crankshaft Speed/Position – Data Erratic, Intermittent, or Incorrect. Loss of signal from crankshaft sensor.

This fault code is recorded when the electronic control module (ECM) does not receive a signal from the crankshaft engine speed sensor, or the signal it receives is degraded.

Possible causes:

1)Open circuit on the supply, signal, or return circuits in the sensor, engine harness, or ECM
2)Short circuits to ground or return circuits in the sensor, engine harness, or ECM
3)Short circuits to a voltage source in the sensor, engine harness, or ECM
4)Damage to the sensor target teeth or tone wheel.

INSITE? electronic service tool monitor parameter associated with this fault code and sensor include:

1)Engine speed sensor state.

If this fault code occurs intermittently, look closely for causes of intermittent harness connections such as loose or worn pins in the engine harness connectors.

Possible repairs:

1)Replace the crankshaft engine speed sensor.
2)Repair or replace the engine harness.
3)Replace the ECM.