Pinpoint Test B : DTC P187C:00 And P187D:00: Notes
WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
Refer to Two Wheel Drive/Four Wheel Drive Systems for schematic and connector information.
Normal Operation
When the ELDMSS is engaged to lock the rear differential, the TCCM sends a PWM signal to the ELD field coil through the differential lock control circuit. This PWM signal is initially 98% duty cycle to lock the differential and then tapers off to a lower duty cycle once the differential is locked. If the differential lock control circuit is open or shorted to ground, the TCCM senses a signal is not reaching the differential and sets a DTC.
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| P187C:00 | Differential Lock-Up Control Circuit/Open: No Sub Type Information | This DTC sets when the TCCM senses the differential lock control circuit is open. The ELD differential is not engaged. |
| P187D:00 | Differential Lock-Up Control Circuit Low: No Sub Type Information | This DTC sets when the TCCM senses the differential lock control circuit is shorted to ground. The ELD differential is not engaged. |
Possible Sources
- Wiring, terminals or connectors
- TCCM