Cummins ISX CM870 (2003-06) Fault Code: 687 PID: P103 SPN: 103 FMI: 1/18 Turbocharger 1 Speed – Data Valid But Below Normal Operating Range – Moderately Severe Level. Low turbocharger speed detected by the engine control module (ECM).

This fault may come active if the electronic control module (ECM) senses boost pressure and engine speed while at the same time a turbocharger speed signal is not present.

Possible causes:

1)Turbocharger speed sensor
2)Turbocharger speed sensor o-ring
3)Engine harness
4)Barometric pressure sensor
5)Intake manifold pressure sensor
6)Replace the ECM.
This fault becomes inactive any time the speed signal from the turbocharger speed sensor returns.

If the calibration software phase is less than 5.0.0.0 and this fault code is active at key-on with the engine not running, the intake manifold pressure signal or barometric pressure sensor signal is inaccurate. Use INSITE? electronic service tool, Data Logger/Monitor to view the calibration software phase.

Make sure only one turbocharger speed sensor o-ring is present. If the old turbocharger speed sensor o-ring remained when the new turbocharger speed sensor and turbocharger speed sensor o-ring were installed, this will create excessive clearance and the turbocharger sensor will not read the turbocharger speed, causing the fault.

Possible repairs:

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