What Does C1138 Mean?
This code indicates the control module has detected that the gear select position sensor circuit is shorted to battery voltage. The gear select sensor monitors lateral shifter position to determine which gear plane is selected. A short to battery on this circuit provides a constant high-voltage reading that masks the actual shifter position.
Common Causes
35%
Chafed wiring in the shifter area where the signal wire contacts a power wire from adjacent circuits
25%
Failed gear select position sensor with internal short between signal output and power supply pins
25%
Corroded connector pins causing cross-contact between signal and power terminals due to debris or moisture buildup
15%
Previous wiring repair with incorrect routing or splicing that introduced a short to a powered circuit
Diagnostic Steps
1
Step 1: Disconnect the gear select sensor connector and measure voltage on the signal wire at the control module side. Battery voltage present with the sensor disconnected confirms a harness-level short.
2
Step 2: With the sensor disconnected, check continuity between the signal wire and all power supply wires in the harness bundle. Any continuity indicates insulation failure.
3
Step 3: Visually inspect wiring from the shifter mechanism through the console and to the module for chafing, melted insulation, or improper splices.
4
Step 4: Test the sensor by measuring resistance between signal output and power input pins. Low resistance indicates internal sensor failure.
5
Step 5: Repair or replace the faulty component, clear codes, and verify proper gear select voltage in live data while moving the shifter laterally through all gate positions.
Estimated Repair Cost
$100 - $350
Parts + labor, varies by vehicle and location
This code indicates the control module has detected that the gear select position sensor circuit is shorted to battery voltage. The gear select sensor monitors lateral shifter position to determine which gear plane is selected. A short to battery on this circuit provides a constant high-voltage read...
The most common cause of C1138 (Gear Select position short to Battery) is: Chafed wiring in the shifter area where the signal wire contacts a power wire from adjacent circuits
Typical repair costs for C1138 range from $100 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Electronic drivetrain management may be impaired. Vehicle is safe to drive manually. Repair at convenience.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1138 to identify the root cause.
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Quick Info
Category
Chassis
System
Transmission / Drivetrain Control
Difficulty
Type
Manufacturer
Recommended Tools
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