OBD-II DTC P1820 – Transmission 4-Wheel Drive Mode Select Short Circuit To Ground
DTC P1820 meaning
DTC P1820 refers to a diagnostic trouble code that indicates a short circuit to ground in the transmission 4-wheel drive mode select circuit. This code is specific to the vehicle’s transmission control module (TCM) and is triggered when the TCM detects an abnormal voltage level in the mode select circuit, suggesting that the circuit is shorted to ground.
DTC P1820 symptoms
Common symptoms associated with DTC P1820 may include:
- Inability to engage or switch between 4-wheel drive modes
- Warning lights on the dashboard, such as the check engine light
- Erratic or unexpected behavior of the transmission
- Transmission may remain in 2-wheel drive mode
DTC P1820 causes
Several factors can lead to the occurrence of DTC P1820, including:
- Wiring issues, such as damaged or frayed wires in the mode select circuit
- Faulty connectors that may be corroded or loose
- Defective transmission control module (TCM)
- Short circuits caused by moisture or foreign objects
DTC P1820 seriousness
The seriousness of DTC P1820 can vary depending on the vehicle’s use and the specific symptoms present. However, it is generally considered a moderate issue because:
- It can affect the vehicle’s ability to switch between drive modes, impacting traction and handling
- Ignoring the code may lead to further transmission issues
- It can result in reduced vehicle performance and safety concerns
How to diagnose DTC P1820
To diagnose DTC P1820, follow these steps:
- Use an OBD-II scanner to confirm the presence of the P1820 code
- Inspect the wiring and connectors related to the transmission mode select circuit for damage or corrosion
- Check for any additional trouble codes that may provide more context
- Test the voltage and continuity of the mode select circuit using a multimeter
- Examine the transmission control module for faults or failures
How to fix DTC P1820 step-by-step instructions
To fix DTC P1820, follow these step-by-step instructions:
- Identify and repair any damaged wiring or connectors in the mode select circuit
- Ensure all connections are secure and free from corrosion
- If the wiring is intact, test the transmission control module for proper operation
- Replace the TCM if it is found to be defective
- Clear the DTC using an OBD-II scanner and test drive the vehicle to ensure the issue is resolved
How to erase DTC P1820
To erase DTC P1820, follow these steps:
- Connect an OBD-II scanner to the vehicle’s diagnostic port
- Turn on the ignition without starting the engine
- Navigate to the “Erase Codes” or “Clear DTCs” option on the scanner
- Confirm the action to clear the trouble codes
- Disconnect the scanner and start the vehicle to check if the code reappears
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