Ignition Sequence
When the ignition is turned on, the ICU runs a self-check. See Fig.. Observing the ignition sequence is a good way to ensure the ICU is functioning properly.
Fig. 1, Ignition Sequence
Important: Do not crank the engine until the ICU self-check is complete.
When the ignition is turned on, the following actions should occur:
-
electronic gauges complete a full sweep of their dials
-
some warning and indicator lamps illuminate, then are extinguished
-
audible alert sounds until sufficient air pressure builds up in the primary and secondary air systems
-
DEF level indicator illuminates all segments green, then turns them off one at a time before turning the leftmost segment amber, then red
-
software revision level of the ICU is displayed on the driver message center, followed by active faults
Note: Air gauges do not complete a sweep of their dials during the ignition sequence.
Important: If any red or amber warning and indicator lamps, or telltales, do not illuminate during the ICU self-check, take the vehicle to an authorized Freightliner service facility as soon as possible. If any of the red or amber telltales do not go out after the self-check completes, use Table. to determine if the lamp illuminated indicates a problem requiring service.
If the ICU receives active fault codes, it displays them one after the other until the parking brake is released or the ignition is turned off. Once the parking brake is completely released, the ICU displays the odometer. If there are no active faults, the ICU displays the odometer after the self-check completes.
Note: If active faults are present, take the vehicle to an authorized Freightliner service facility as soon as possible.
Table 1, Common Warning and Indicator Lamps and ICU Messages
|
Common Warning and Indicator Lamps and ICU Messages |
|||
|
Lamp Description |
Color |
||
 |
STOP Engine1 |
Indicates a serious fault that requires engine shutdown immediately. The engine protection system will reduce the maximum engine torque and speed, and, if the condition does not improve, will shut down the engine within 30 to 60 seconds. Safely bring the vehicle to a stop on the side of the road and shut down the engine as soon as the red light is seen. If the engine shuts down while the vehicle is in a hazardous location, turn the key to the OFF position for a few seconds, then restart the engine and move the vehicle to a safer location. |
Red |
 |
High Coolant Temperature |
Indicates the coolant temperature is above the maximum allowable temperature. |
Red |
 |
Low Air Pressure (EPA07) |
Indicates air pressure in the primary or secondary reservoir has dropped below approximately 70 psi (483 kPa). |
Red |
 |
Low Air Pressure (EPA10 and Newer) |
Indicates air pressure in the primary or secondary reservoir has dropped below approximately 70 psi (483 kPa). |
Red |
 |
Low Engine Oil Pressure |
Indicates the engine oil pressure is below the minimum allowable pressure. |
Red |
 |
Parking Brake (EPA07) |
Indicates the parking brake is engaged, or hydraulic brake fluid pressure is low. An audible alert activates when the vehicle is moving over 2 mph (3 km/h) with the parking brake set. |
Red |
 |
Parking Brake (EPA10 and Newer) |
Indicates the parking brake is engaged. |
Red |
 |
Low Battery Voltage |
Indicates that battery voltage is 11.9 volts or less. |
Red |
 |
Unfastened Seat Belt |
Activates with an audible alert when the system detects that the parking brake is off and the driver seat belt is not fastened on some vehicles. On other vehicles, this lamp illuminates for 15 seconds when the ignition is first turned on. |
Red |
 |
CHECK Engine1 |
Indicates an engine condition (low oil pressure, low coolant level, high coolant temperature, high DPF soot level, or uncontrolled DPF regeneration) that requires correction. Correct the condition as soon as possible. If the condition worsens, the STOP engine lamp will illuminate. |
Amber |
 |
High Exhaust System Temperature (HEST)1 |
Slow (10-second) flashing indicates a regeneration (regen) is in progress. IMPORTANT: When the HEST lamp is illuminated, do not park the vehicle near flammable material. Solid illumination indicates high exhaust temperatures at the outlet of the tail pipe when speed is below 5 mph (8 km/h). |
Amber |
 |
Diesel Particulate Filter (DPF) Status |
Solid illumination indicates a regen is required. Change to a more challenging duty cycle (such as highway driving ) to raise exhaust temperatures for at least twenty minutes, or perform a parked regen. Blinking indicates that a parked regen is required immediately. An engine derate and shutdown will occur. |
Amber |
 |
Malfunction Indicator Lamp (MIL) |
Indicates an emissions-related fault. See the engine operation manual for details. |
Amber |
 |
Vehicle ABS |
Momentary illumination indicates the vehicle ABS is engaged. Solid illumination indicates a problem with the vehicle ABS. Repair the ABS immediately to ensure full braking capability. |
Amber |
 |
Trailer ABS |
Momentary illumination indicates the trailer ABS is engaged. Solid illumination indicates a problem with the trailer ABS. Repair the ABS immediately to ensure full braking capability. |
Amber |
 |
No Charge |
Indicates the alternator is not properly powering the electrical system. |
Amber |
 |
Water in Fuel |
Indicates the fuel may contain water. Drain any water collected in the fuel/water separators. |
Amber |
 |
Fuel Filter Restriction |
Indicates the fuel filter is clogged and requires service. |
Amber |
 |
Optimized Idle |
Indicates optimized idle is enabled. |
Amber |
 |
Check Transmission |
Indicates an undesirable transmission condition. |
Amber |
 |
Transmission Overheat |
Indicates high transmission temperature. |
Amber |
 |
Wait To Start (EPA07/EPA10) |
Indicates that the system is preventing the starter from cranking. This can occur when the ignition switch is turned to START before the gauge sweep has completed, or if the starter has overheated. Turn the ignition switch back to ON, wait for the lamp to go out, then turn the ignition switch to START again. |
Amber |
 |
Start Blocked (GHG14 only) |
Indicates that the system is preventing the starter from cranking. This can occur when the ignition switch is turned to START before the gauge sweep has completed, or if the starter has overheated. Note: Illumination of the Start Blocked lamp does not indicate a problem with the starter. Turn the ignition switch back to ON, wait for the lamp to go out, then turn the ignition switch to START again. |
Amber |
 |
Wheel Spin (pre-EPA16) |
Flashing indicates the ATC system is active, or the ATC button has been pressed to allow wheel slip. Solid illumination indicates ATC is shut off or unavailable due to a system fault. In the event of a system fault, repair the ATC system immediately to ensure full braking capability. |
Amber |
 |
Stability Event (EPA16 and newer) |
Flashing indicates a stability event has been detected, and the ESC system is active. Solid illumination indicates a problem with the stability system. Repair the ESC system immediately to ensure full stability capability. |
Amber |
 |
ATC Deactivated (EPA16 and newer) |
Flashing indicates the ATC SPIN button has been pressed to allow wheel slip. Solid illumination indicates ATC is shut off or unavailable due to a system fault. In the event of a system fault, repair the ATC system immediately to ensure full braking capability. |
Amber |
 |
Roll Stability (pre-EPA16) |
Momentary illumination indicates that a stability event has occurred. On vehicles that are also equipped with ATC, flashing indicates the ATC button has been pressed to allow wheel slip. Solid illumination indicates ATC is shut off or unavailable due to a system fault. In the event of a system fault, repair the ATC system immediately to ensure full braking capability. |
Amber |
 |
Hill Start Aid (HSA) Override |
Indicates the HSA switch has been pressed to override the hill start assist feature. |
Amber |
 |
Engine Brake 2 |
Indicates the engine brake is enabled. |
Green |
 |
Left-Turn Signal |
Flashing indicates the outside left-turn signal lights are activated. |
Green |
 |
Right-Turn Signal |
Flashing indicates the outside right-turn signal lights are activated. |
Green |
 |
Cruise Control 2 |
Indicates the cruise control is enabled. NOTE: The ICU4Me does not have a green cruise control telltale. |
Green |
 |
High-Beam Headlights |
Indicates the high-beam headlights are on. |
Blue |
- See Fig. for an explanation of the aftertreatment system (ATS) warning indicators, and actions required to avoid further engine protection steps.
- On vehicles equipped with the ICU3S, this information is displayed on the driver message center.
Table 1, Common Warning and Indicator Lamps and ICU Messages
