Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
The cost to diagnose the P1857 code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.
The Mode Select Switch (MSS) communicates the operator's choice to the Transfer Case Control Module (TCCM). As the TCCM commands the gearmotor encoder assembly to 4H mode, the transfer case shift fork moves to engage 4H mode which also engages the dual-cone synchronizers to bring the front driveline to the same speed as the rear driveline. The TCCM also activates the hublock vacuum solenoid, providing a vacuum and engaging the Constant Vacuum Hublock (CVH) at each front wheel. If the vehicle is not responding to the operator's intentions, systematically check the necessary inputs and outputs of the TCCM, components of the transfer case, CVH components, and axle shafts. Check all circuits for opens and shorts to power or ground.
Need more information on how to fix the P1857 code? Get Access to Factory Service Manuals
Get the P1857 code diagnosed by a professional: Find a repair shop in your area