What Does P1863 Mean?
The TCM has detected an open circuit in the power supply to the transfer case contact plate. There is no continuity in the power circuit, meaning the contact plate is not receiving necessary voltage to operate.
Common Causes
35%
Broken wire in power supply harness to contact plate
30%
Blown fuse or failed relay in transfer case power circuit
20%
Disconnected or loose power connector at contact plate
10%
Corroded connector terminal creating open circuit
5%
Failed internal contact plate power distribution
Diagnostic Steps
1
Step 1: Verify all fuses in transfer case power circuit are intact and check for blown fuses
2
Step 2: Test relay operation by checking for power at relay output terminal
3
Step 3: Check for voltage at power supply connector to contact plate with key on
4
Step 4: Perform continuity test from power source through relay, fuse, and harness to contact plate
5
Step 5: Isolate break location by testing at intermediate points in power distribution circuit
Estimated Repair Cost
$80 - $700
Parts + labor, varies by vehicle and location
The TCM has detected an open circuit in the power supply to the transfer case contact plate. There is no continuity in the power circuit, meaning the contact plate is not receiving necessary voltage to operate.
The most common cause of P1863 (Transmission Transfer Case Contact Plate Power Open Circuit) is: Broken wire in power supply harness to contact plate
Typical repair costs for P1863 range from $80 to $700, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Transfer case will not operate, limiting vehicle to 2WD mode. Significantly reduces traction capability in poor weather or off-road conditions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1863 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Transmission/Transfer Case Control
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
