What Does P1850 Mean?
Duplicate condition of P1845 - the differential lock-up feedback switch circuit is shorted to ground. This redundant code may indicate a secondary feedback circuit or alternative lock position sensor with ground fault.
Common Causes
40%
Damaged wiring harness grounded to transfer case housing or vehicle frame
25%
Failed feedback switch with internal short to ground or case
20%
Water intrusion in connector causing ground path through corrosion
15%
Wiring pinched during service or crushed by transfer case skid plate
Diagnostic Steps
1
Step 1: Disconnect differential lock feedback switch connector and dry/clean if moisture present
2
Step 2: Measure resistance from signal wire terminal to ground at harness side - should read infinite
3
Step 3: If low resistance found, isolate harness sections to locate ground fault point
4
Step 4: Inspect wiring near mounting brackets, exhaust, and skid plate attachment points
5
Step 5: Repair grounded wiring, replace damaged connectors, or replace switch if internal ground fault confirmed
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
Duplicate condition of P1845 - the differential lock-up feedback switch circuit is shorted to ground. This redundant code may indicate a secondary feedback circuit or alternative lock position sensor with ground fault.
The most common cause of P1850 (Transmission Transfer Case Differential Lock-Up Feedback Switch Short Circuit To Ground) is: Damaged wiring harness grounded to transfer case housing or vehicle frame
Typical repair costs for P1850 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Differential lock feedback circuit failure may prevent proper 4WD engagement or cause differential to remain locked, creating handling issues and potential drivetrain damage.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1850 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transfer Case / 4WD System
Difficulty
Type
Manufacturer
Recommended Tools
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