C4.4 and C6.6 Industrial Engines and Engines for Caterpillar Built Machines Caterpillar

The Electronic Control Module (ECM) detects the following conditions:

• The signal voltage from the intake manifold air temperature sensor is greater than 4.95 Volts DC for more than eight seconds.

• Engine coolant temperature is above −10 °C (15.0 °F).

• The ECM has been powered for at least two seconds.

• Diagnostic code 0168-01 is not active.

System Response:

If equipped, the warning light will come on. The ECM will log the diagnostic code.

The ECM will use the default value of 70 °C (158 °F) for the intake manifold air temperature. "Voltage High" will be displayed next to the status for "Intake Manifold Air Temperature" on the electronic service tool.

• Poor stability

• Poor cold running

• White smoke

• Black smoke

• Poor acceleration under load

This fault can be caused by an open circuit or a short to a power source.

Test Step 1. Perform the following diagnostic procedure: Engine Temperature Sensor Open or Short Circuit - Test

Results:

• OK - STOP