C1138: Gear Select position short to Battery

Definition

The OBD2 code C1138 indicates a fault where the gear select position sensor is shorted to the battery, which can affect the transmission's ability to determine the correct gear position

Common causes

Faulty gear position sensor
Damaged wiring or connectors
Short circuit in the wiring harness
Corroded connectors
Malfunctioning transmission control module (TCM)
Incorrectly installed or misaligned gear selector
Electrical interference from other components

Common misdiagnoses

Faulty transmission range sensor
Wiring issues or shorts in the harness
Malfunctioning powertrain control module (PCM)
Defective gear shift lever assembly
Issues with the vehicle's battery or charging system
Faulty connectors or terminals
Incorrectly calibrated transmission control module (TCM)

Troubleshooting steps

1. Check the Vehicle's Battery and Charging System
2. Ensure the battery is fully charged and in good condition
3. Inspect the alternator and charging system for proper operation
4. Inspect Wiring and Connectors
5. Examine the wiring harness and connectors associated with the gear selector position sensor for any signs of damage, corrosion, or loose connections
6. Look for any frayed wires or shorts that may be causing the sensor to read incorrectly
7. Test the Gear Selector Position Sensor
8. Use a multimeter to test the resistance and voltage output of the gear selector position sensor
9. Compare the readings to the manufacturer's specifications to determine if the sensor is functioning correctly
10. Check for Ground Issues
11. Ensure that the ground connections for the gear selector position sensor and related components are secure and free of corrosion
12. Inspect the Transmission Control Module (TCM)
13. Check for any fault codes in the TCM that may provide additional information about the issue
14. If necessary, reprogram or replace the TCM if it is found to be faulty
15. Clear Codes and Test Drive
16. After performing any repairs or adjustments, clear the OBD-II codes using a scan tool
17. Take the vehicle for a test drive to see if the code reappears
18. Consult Technical Service Bulletins (TSBs)
19. Check for any TSBs related to the specific make and model of the vehicle, as there may be known issues or recalls that address the C1138 code
20. Seek Professional Help
21. If the issue persists after performing the above steps, consider consulting a professional mechanic or technician who has experience with transmission issues and OBD-II diagnostics. By following these steps, you should be able to identify and resolve the underlying issue causing the C1138 code

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Check the Vehicle's Battery and Charging System

2. Ensure the battery is fully charged and in good condition

3. Inspect the alternator and charging system for proper operation

4. Inspect Wiring and Connectors

5. Examine the wiring harness and connectors associated with the gear selector position sensor for any signs of damage, corrosion, or loose connections

6. Look for any frayed wires or shorts that may be causing the sensor to read incorrectly

7. Test the Gear Selector Position Sensor

8. Use a multimeter to test the resistance and voltage output of the gear selector position sensor

9. Compare the readings to the manufacturer's specifications to determine if the sensor is functioning correctly

10. Check for Ground Issues

11. Ensure that the ground connections for the gear selector position sensor and related components are secure and free of corrosion

12. Inspect the Transmission Control Module (TCM)

13. Check for any fault codes in the TCM that may provide additional information about the issue

14. If necessary, reprogram or replace the TCM if it is found to be faulty

15. Clear Codes and Test Drive

16. After performing any repairs or adjustments, clear the OBD-II codes using a scan tool

17. Take the vehicle for a test drive to see if the code reappears

18. Consult Technical Service Bulletins (TSBs)

19. Check for any TSBs related to the specific make and model of the vehicle, as there may be known issues or recalls that address the C1138 code

20. Seek Professional Help

21. If the issue persists after performing the above steps, consider consulting a professional mechanic or technician who has experience with transmission issues and OBD-II diagnostics. By following these steps, you should be able to identify and resolve the underlying issue causing the C1138 code