What Does P1845 Mean?
The transfer case differential lock-up feedback switch circuit is shorted to ground. The control module detects constant ground signal when it should receive variable voltage feedback based on differential lock engagement status.
Common Causes
40%
Damaged wiring harness with wire grounded to transfer case housing or frame
25%
Failed differential lock feedback switch with internal short to ground
20%
Corroded connector with moisture causing ground short
15%
Pinched wiring during transfer case service or installation
Diagnostic Steps
1
Step 1: Disconnect differential lock feedback switch connector and check for corrosion or moisture
2
Step 2: Measure resistance from signal wire to ground at harness connector - should read infinite (open circuit)
3
Step 3: If resistance to ground is low, isolate wiring sections to locate short to ground
4
Step 4: Inspect wiring routing near transfer case and exhaust components for damage
5
Step 5: Repair wiring or replace switch as needed, ensure proper routing away from heat/pinch points
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
The transfer case differential lock-up feedback switch circuit is shorted to ground. The control module detects constant ground signal when it should receive variable voltage feedback based on differential lock engagement status.
The most common cause of P1845 (Transmission Transfer Case Differential Lock-Up Feedback Switch Short Circuit To Ground) is: Damaged wiring harness with wire grounded to transfer case housing or frame
Typical repair costs for P1845 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Differential lock function may not operate correctly, potentially causing drivetrain binding or inability to engage 4WD when needed for traction.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1845 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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