Cummins ISX15 CM2250 (2010-12) 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 engine 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.

Component Location
Not Applicable

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

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 lamp 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
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 engine speed drops to normal operating speeds and the diagnostic runs and passes.
The ECM will turn off the red STOP 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
Possible causes of this fault code include:

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.

If Fault Code 234 becomes active only during engine braking, and the engine brakes fail to engage, check for a short circuit to ground in the engine brake wiring harness. The rocker lever cover must be removed to perform this inspection. Repair or replace the engine brake wiring harness as necessary.

Possible Cause:
1) Engine Damage
2) ECM failure