Normal Operation
WARNING: This page is about a different car, the 2013 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
When the MSS is engaged to lock the rear differential, a PWM signal is sent to the ELD field coil by the TCCM through the differential lock control circuit. This PWM signal is initially 98% duty cycle to lock the differential and decreases to 40% duty cycle once the differential is locked. If the differential does not lock, the TCCM continues to send the signal for a set amount of time. Once the differential is locked, the indicator will illuminate steady.
- DTC P185A:00 (Differential Lock-Up Input Switch Circuit High: No Sub Type Information) - When not in locking mode, the TCCM C2371A pin 15 senses whether the ELD mode switch circuit has high voltage and if the differential is always engaged. This DTC will not set unless the MSS is set to 2H or OFF. If the ELD is functioning normally, the differential will immediately lock when the MSS is activated and the ELD operating conditions are qualified. This DTC will only display during the self-test function.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- TCCM