Cummins ISB CM850 (2003-06) Fault Code: 2964 PID: 105 SPN: 105 FMI: 15 Intake Manifold Temperature High – Data Valid But Above Normal Operating Range – Least Severe Level. Intake manifold air temperature signal indicates intake manifold air temperature above engine protection warning limit.

The intake manifold air temperature sensor measures the temperature of the charge-air as it passes through the intake manifold.

Possible causes:

1)Plugged charge-air cooler fins
2)Restricted airflow through the charge-air cooler
3)Undersized charge-air cooler
4)High turbocharger compressor outlet temperature.

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 ECM.
2)Replace the engine harness.
3)Replace the OEM harness.