T-378
3–4
3.4 Air Control Valve (ACV) Description
, restricts engine intake air to raise exhaust temperatures. It is a normally-
open valve that is located on the engine air intake hose. When the DPF requires regeneration and exhaust
temperature is very low (for example, during minimal engine loading and/or extremely cold weather), the ACV is
used for active-assist regeneration. During active-assist regeneration, the ACV changes the air-to-fuel ratio in
order to raise exhaust temperatures high enough for the doser to activate and regenerate the DPF. Refer to
for a description of how regeneration works.
Figure 3.6 Air Control Valve (ACV)
3.5 Emissions Control Module (ECM) Description
The Emissions Control Module (ECM),
, monitors the EES parameters, using an internal back pressure
sensor, along with temperature sensors mounted in three locations of the exhaust system. Based on the
parameters, the ECM will initiate automatic regeneration when needed. Further diagnosing with the ECM requires
the ECM Service Tool software. Refer to
chapter for procedures.
Figure 3.7 Emissions Control Module (ECM)
The ECM will signal to the service light,
, as part of alarm notification. A unit with an illuminated service
light indicates immediate service is needed, and will continue to operate for up to 250 hours in order to protect load
and allow adequate time for delivery. After 250 hours, the unit will shut down until the EES is repaired.
Figure 3.8 Service Light
