How to use Intake Air Heater Override function on Cummins Insite?

Figure 1.1 – Wait to start preheating (Murphy PowerView)

If the Engine ECU broadcasts a “Wait to Start” message, this screen appears. Engine manufacturers generally advise against starting the engine while this message is active. Once the ECU stops broadcasting the message, the screen will no longer be displayed.

Intake air heater control

The intake air heater control assists combustion during cold starts by managing the heating elements in the engine’s intake air system. The ECM controls these heating elements in two phases: pre-heat (before cranking) and post-heat (after startup). The heater remains active based on the intake manifold temperature at key-on.

Pre-heat (before cranking): At key-on, the ECM checks the intake manifold air temperature. It then turns on the Wait to Start lamp and energizes the intake air heaters (see figure 1.1). After a calibrated delay, the ECM turns off the heaters, and the Wait to Start lamp turns off. The operator can then start the engine. Pre-heat duration increases in colder conditions.

Post-heat (after startup): During cranking, the intake air heater is turned off to allow maximum current for the starter. After a successful engine start, the ECM resumes cycling the heater based on the intake manifold air temperature at key-on. This cycle may run for several minutes in extreme cold to control white smoke emissions after startup.

Features and parameters

Figure 1.2 – Intake air heater (Enable)

This feature controls the heating elements, which activate to warm the intake air in cold temperatures. Depending on the engine, there may be one or multiple intake air heaters, controlled by the ECM via a relay connected to the battery supply.

During post-heat, the ammeter gauge may fluctuate as the heater cycles on and off.

→ To avoid hard starts in cold temperatures, always wait for the “Wait to Start” lamp to turn off before attempting to start the engine (see figure 1.1).

Intake air heater override

This test allows you to manually override the intake air heater controls, turning the heater solenoid(s) ON or OFF. This is useful for troubleshooting startability issues, white smoke, and intake air heater fault codes. When relays are energized, an audible click should be heard.

For some engines:

12V grid heaters are wired in parallel, with two drivers, each controlling one grid heater.

24V grid heaters are wired in series, with one driver controlling both grid heaters (the second driver is unused and will not display in INSITE).

The pre-heat cycle activates the intake heater(s) at key-on, depending on intake air temperature. They operate until the intake manifold temperature reaches 66°F (18.9°C).

To prevent burnout, some engine applications include a timer that turns the heater off even if it’s commanded on. In applications without a timer, the Intake Air Heater Override Test will automatically shut it off after a short time.

To test the intake air heater

1). Connect diagnostic adapter tools to the Cummins engine’s diagnostic port.

→ Read more: How to connect CUMMINS engines using CUMMINS INSITE software.

2). Select Intake Air Heater Override from the ECM Diagnostic Tests Wizard window.