C1138 – OBD-II DTC

OBD-II DTC C1138 – Gear Select position short to Battery

DTC C1138 meaning

DTC C1138 refers to a diagnostic trouble code indicating a “Gear Select Position Short to Battery” issue. This code is triggered when the vehicle’s onboard diagnostic system detects an electrical short circuit in the gear selection circuit, which may lead to incorrect gear position readings. This can affect the transmission’s ability to function properly, potentially leading to erratic shifting or failure to shift at all.

DTC C1138 symptoms

Common symptoms associated with DTC C1138 may include:

• Transmission not shifting properly
• Erratic or unexpected gear changes
• Warning lights illuminated on the dashboard
• Vehicle may enter limp mode
• Difficulty in selecting gears

DTC C1138 causes

Several factors can lead to the triggering of DTC C1138, including:

• Faulty gear position sensor
• Wiring issues, such as frayed or damaged wires
• Corrosion or poor connections in the electrical circuit
• Short circuit in the transmission control module
• Faulty transmission control module (TCM)

DTC C1138 seriousness

DTC C1138 is considered a serious issue as it can lead to significant transmission problems. If not addressed, it may result in:

• Inability to drive the vehicle safely
• Increased wear and tear on the transmission
• Potential for complete transmission failure

How to diagnose DTC C1138

To diagnose DTC C1138, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the code.
2. Inspect the gear position sensor and its wiring for damage or corrosion.
3. Check for any additional trouble codes that may provide more context.
4. Test the voltage and ground at the gear position sensor.
5. Examine the transmission control module for faults.

How to fix DTC C1138 step-by-step instructions

To fix DTC C1138, follow these steps:

1. Disconnect the vehicle’s battery to ensure safety.
2. Inspect and repair any damaged wiring or connectors related to the gear position sensor.
3. Replace the gear position sensor if it is found to be faulty.
4. Check and repair the transmission control module if necessary.
5. Reconnect the battery and clear the DTC using an OBD-II scanner.
6. Test drive the vehicle to ensure the issue is resolved.

How to erase DTC C1138

To erase DTC C1138, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the “Erase Codes” or “Clear DTCs” option on the scanner.
4. Confirm the action to clear the trouble codes.
5. Disconnect the scanner and start the vehicle to check if the code returns.

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