PACCAR PX-6 CM2150 (2007-09) Fault Code: 334 PID: 110 SPN: 100 FMI: 2 Engine Coolant Temperature – Data Erratic, Intermittent, or Incorrect. The engine coolant temperature reading is not changing with engine operating conditions.

Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe® Online for applicable fixes to the calibration stored in the ECM. If necessary, recalibrate the ECM.

Two different failure modes of the engine coolant temperature sensor can trigger this fault code. Either the sensor is not reading ambient air temperature after an extended period with the engine not running or the engine coolant temperature is not changing with engine operating conditions.

Possible causes:

1)Stuck in-range engine coolant temperature sensor
2)High resistance in the engine coolant temperature sensor signal or return lines.

Possible repairs:

1)Replace the thermostat.
2)Replace the engine coolant temperature sensor.
3)Replace the ECM.
4)Repair or replace the engine harness.