What Does P2839 Mean?
The TCM has detected an abnormally high voltage signal from the shift fork B position sensor circuit. Voltage exceeds the expected maximum threshold, indicating an open circuit or short to power condition.
Common Causes
35%
Open circuit in shift fork B position sensor ground wire
30%
Short to voltage in sensor signal wire
25%
Failed shift fork position sensor B (internal open)
8%
Disconnected or damaged sensor connector
2%
TCM internal circuit fault
Diagnostic Steps
1
Step 1: Check shift fork B position sensor connector for proper connection and terminal integrity
2
Step 2: Measure voltage at sensor signal wire - reading near battery voltage indicates high circuit fault
3
Step 3: Disconnect sensor and recheck signal wire voltage with key on to identify short to power in harness
4
Step 4: Verify sensor ground circuit has continuity to good chassis ground
5
Step 5: Replace sensor if wiring and ground circuits test within specification
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
The TCM has detected an abnormally high voltage signal from the shift fork B position sensor circuit. Voltage exceeds the expected maximum threshold, indicating an open circuit or short to power condition.
The most common cause of P2839 (Shift Fork "B" Position Circuit High) is: Open circuit in shift fork B position sensor ground wire
Typical repair costs for P2839 range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
May result in improper gear selection, harsh shifting, or transmission entering limp mode. Should be repaired promptly to avoid potential transmission damage from incorrect shift control.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2839 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 Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
