Principles of Operation

Electronic Locking Differential (ELD) System

Principles of Operation

Electronic Locking Differential (ELD) System

The Electronic Locking Differential (ELD) system allows the operator to lock the rear differential side gears. When the ELD is engaged both rear wheels turn at the same speed, providing added traction on slippery and/or off road surfaces. The operator can engage the ELD per the charts below:

ELD Engagement Speeds - 4WD Vehicles





a The ELD system engages/re-engages at or below the speed noted.

ELD Engagement Speeds -2WD Vehicles





a The ELD system engages/re-engages at or below the speed noted.

When the operator sets the Mode Select Switch (MSS) to either 4L, 4H or ON position (depending upon vehicle option content) to activate the ELD, the ELD icon displays in the Instrument Panel Cluster (IPC) message center. If the vehicle is driven above the disengage speed, the IPC message center no longer displays the ELD icon, alerting the operator that the ELD is disengaged. Once the vehicle drops below the re-engage speed, the IPC message center displays the ELD icon again. If there is a malfunction with the ELD system, a "CHECK LOCKING DIFFERENTIAL" message is displayed in the IPC message center, letting the operator know the ELD is not engaged.

The differential locks when a Pulse Width Modulated (PWM) controlled magnetic field coil located inside the differential energizes. A collar within the differential moves toward a differential side gear and engages a dog clutch within the differential. This locks the differential side gears and creates the locked differential.

The Transfer Case Control Module (TCCM) activates the ELD. When the ELD is engaged, the TCCM sends PWM voltage to the ELD field coil located in the differential. This voltage is initially 98% duty cycle, and then tapers off to 40% duty cycle after 30 seconds. In order for the TCCM to activate the ELD, certain conditions must be met.

TCCM Input Conditions

- MSS set to ELD position
- Average rear wheel speed versus average front wheel speed must be less than 15 km/h (9 mph) (via High Speed Controller Area Network (HS-CAN) communication from ABS module)
- Operating range (voltage between 9-16 volts)
- DTC setting range (voltage between 10-15 volts)
- Ignition in the ON position
- Throttle Position (TP) less than 50%