Cummins ISB CM850 (2003-06) Fault Code: 234 (Auto) PID: 190 SPN: 190 FMI: 0 Engine Crankshaft Speed/Position – Data Valid But Above Normal Operating Range – Most Severe Level. Engine speed signal indicates engine speed above engine protection limit.

Cummins ISB CM850 (2003-06) Fault Code: 234 (Auto) PID: 190 SPN: 190 FMI: 0 Engine Crankshaft Speed/Position – Data Valid But Above Normal Operating Range – Most Severe Level. Engine speed signal indicates engine speed above engine protection limit.

Possible causes:

1)External fuel sources drawn into the intake air passage
2)Reverse powering (motoring) of the engine
3)Tampering of the engine speed/position sensors.

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

The sensor return configuration for Euro 4 ISB engines has been changed for automotive wiring harnesses manufactured from February 2012 onward. The new style wiring harnesses can be be identified using the method below:

1)Disconnect the ECM connector
2)Disconnect the camshaft position sensor
3)Disconnect the intake manifold pressure/temperature sensor
4)Check for continuity between the intake manifold pressure/temperature sensor RETURN pin and the camshaft position sensor RETURN pin
5)Check for continuity between ECM pin 47 and the camshaft position sensor RETURN pin
6)Use the table below to determine which harness is fitted to the engine.

NOTE: QSB engines, all C series engines, and all L series engines are not affected by this change.

Possible repairs:

1)Replace the crankshaft engine speed sensor.
2)Replace the camshaft engine position sensor.
3)Replace the ECM.