Cummins ISX12 CM2250 (2010-12) Fault Code: 686 PID: 103 SPN: 103 FMI: 2 Turbocharger 1 Speed- Data Erratic, Intermittent, or Incorrect

Circuit Description
The turbocharger speed sensor is a variable reluctance speed sensor. It consists of a coil of wire and an iron core. The target on the turbocharger shaft is a ground flat in the center of the shaft. As the flat on the turbocharger shaft spins past the speed sensor, a signal is generated. The ECM interprets this signal and converts it to a turbocharger speed reading.

Component Location
The turbocharger speed sensor is mounted in the center housing of the turbocharger.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the engine is operating.

Conditions for Setting the Fault Codes
The ECM detects a turbocharger speed that is greater than the speed that is physically achievable by the turbocharger.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
The ECM will estimate the turbocharger speed.
Conditions for Clearing the Fault Code
To validate the repair using a Diagnostic Road Test, utilize a route that incorporates both stop-and-go city driving and steady state highway driving. It may be necessary to load the unit for certain diagnostics in the ECM to run.
To validate the repair using a Chassis Dynamometer Test, utilize a routine that incorporates acceleration and motoring events, steady state highway operation, and load. This will simulate normal driving and allow the diagnostics in the ECM to run.
The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The ECM will turn off the amber CHECK ENGINE lamp after the diagnostic runs and passes.
The ?Reset All Faults? command in INSITE? electronic service tool can be used to clear active and inactive faults.

Shop Talk
Usually this fault code indicates a faulty turbocharger speed sensor or incorrect speed signals from the sensor. This fault can be caused by malfunctions in the following components:

Turbocharger speed sensor
Engine harness
ECM power supply or grounds
Electronic vehicle accessories which emit excessive electromagnetic interference.
If the fault occurs intermittently:

Look for causes of intermittent open circuit or short circuits in the turbocharger speed sensor circuit (including the speed sensor pigtail connector).
Look for sources of electronic noise such as poorly installed vehicle electronic components.
Be sure that the vehicle chassis grounds are in good condition.
Be sure that the ECM power supply and ground circuits are in good condition and that this power supply is not shared with other vehicle electronics.

Possible Cause:
1) Turbocharger Speed Sensor Failure
2) Engine Harness/ Connector failure
3) ECM calibration