Cummins ISB4.5 CM2150 Fault Code: 234 PID: 190 SPN: 190 FMI: 0 Engine Crankshaft Speed/Position – Data Valid But Above Normal Operating Range – Most Severe Level.

Circuit Description
The crankshaft position and camshaft position sensors are Hall effect type sensors. The electronic control module (ECM) provides a 5 volt supply to the position sensor and a return circuit. As the teeth on the crankshaft speed ring or the dimples in the back of the camshaft gear move past the position sensor, a signal is generated on the position sensor signal circuit. The ECM interprets this signal and converts it to an engine speed. A missing tooth on the crankshaft gear is used to determine the position of the engine by the ECM.

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

Conditions for Setting the Fault Codes
The ECM detects the engine speed has exceeded the calibration limit for excessive engine speed.

Action Taken When the Fault Code is Active
-The ECM illuminates the red STOP ENGINE light immediately when the diagnostic runs and fails.
-Fueling to the engine is stopped until the engine speed drops to normal operating speeds.

Conditions for Clearing the Fault Code
– The ECM will turn off the red STOP ENGINE light and the fault code will go inactive immediately after the engine speed drops to normal operating speeds.
-This fault code can also be cleared with INSITE™ electronic service tool.

Possible Causes
-External fuel sources drawn into the intake air passage
-Reverse powering (motoring) of the engine
-Tampering of the engine speed/position sensors.

Inspect the intake manifold for sources of flammable vapors. Check the turbocharger seals to verify there are no oil leaks. Inspect the engine speed/position sensors for damage or tampering.