DEF Warnings and Engine Limits

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Important: Ignoring the DEF warning lights and not refilling the DEF will result in limited engine power with a speed limit of 5 mph (8 km/h) eventually being applied. See the engine manufacturer's manual for further information.

DEF Level Low—Initial Warning

When the DEF level reads low the following warnings strongly encourage the driver to refill the DEF tank. See Fig..

  • The CHECK engine lamp flashes for 30 seconds when the vehicle is started.

  • The DEF warning lamp illuminates.

  • One bar of the DEF-level lightbar illuminates solid amber.

The DEF tank must be filled to cancel the warning sequence.

  • DEF Warning Lamp (illuminates constantly)

  • DEF-Level Lightbar (1 bar solid amber)

Fig. 1, DEF Level Low—Initial Warning

DEF Level Low—Critical Warning

When the DEF level reads low, the following warnings are activated. See Fig..

  • The CHECK engine lamp flashes for 30 seconds when the vehicle is started.

  • The DEF warning lamp illuminates.

  • One bar of the DEF-level lightbar flashes red.

Engine performance is limited, with progressively harsher engine power limits applied.

The DEF tank must be filled to cancel the warning sequence.

  • DEF Warning Lamp (illuminates constantly)

  • DEF-Level Lightbar (1 bar flashing red)

Fig. 2, DEF Level Low—Critical Warning

DEF Empty

When the DEF level reads empty, the following lamps notify the driver. See Fig..

  • One bar of the DEF-level lightbar flashes red.

  • The DEF warning lamp flashes.

  • The CHECK engine lamp illuminates.

Engine performance is limited, with progressively harsher engine power limits applied.

The DEF tank must be filled to cancel the warning sequence.

Note:  Engine performance is limited.

  • DEF Warning Lamp (flashing)

  • DEF-Level Lightbar (1 bar flashing red)

Fig. 3, DEF Empty Warning

DEF Level Empty and Ignored

If the empty warning is ignored and the DEF is not refilled, the DEF warning lamp flashes, one bar of the DEF-level lightbar flashes red, and the red STOP engine lamp illuminates in addition to the CHECK engine warning lamp. See Fig..

If the DEF tank is not refilled, a 5 mph (8 km/h) speed limit will be applied after the next engine shutdown, or while parked and idling.

Note:  The STOP engine, CHECK engine, and DEF lamps illuminate, engine power is limited, speed limit of 5 mph (8 km/h).

  • DEF Warning Lamp (flashing)

  • DEF-Level Lightbar (1 bar flashing red)

Fig. 4, DEF Empty and Ignored Warning

DEF Quality or SCR Tampering

Notice: Once contaminated DEF or tampering has been detected in the SCR system, the vehicle must be taken to an authorized service center to check the SCR system for damage, and to deactivate the warning light and engine limits.

If contaminated DEF or tampering is detected, the DEF warning light flashes, and engine power is limited with progressively harsher limits applied. If the fault is not corrected, the STOP engine light illuminates and a 5 mph (8 km/h) speed limit is applied after the next engine shutdown, or while parked and idling. See Fig..

Note:
Document Number: 0000107270
Manual Publication Date: 2024-05-07
Topic Publication Date: 2024-07-29