P1629 – OBD-II DTC

OBD-II DTC P1629 – Anti Theft System

DTC P1629 meaning

DTC P1629 refers to an issue with the anti-theft system in a vehicle. This code indicates that the Engine Control Module (ECM) has detected a malfunction related to the vehicle’s security system. The anti-theft system is designed to prevent unauthorized access and ensure that only the registered key or fob can start the engine. When this code is triggered, it typically means that the ECM is unable to verify the key or that there is a communication problem with the anti-theft module.

DTC P1629 symptoms

Common symptoms associated with DTC P1629 may include:

• Engine not starting
• Security light illuminated on the dashboard
• Intermittent starting issues
• Loss of power to the engine
• Key fob not recognized by the vehicle

DTC P1629 causes

Several factors can lead to the triggering of DTC P1629, including:

• Faulty key or key fob
• Malfunctioning anti-theft module
• Issues with the ignition switch
• Wiring problems or poor connections in the anti-theft system
• ECM software issues or corruption

DTC P1629 seriousness

DTC P1629 is considered a serious issue as it can prevent the vehicle from starting. This can lead to inconvenience and potential safety concerns if the vehicle is unable to operate. It is important to address this code promptly to ensure the vehicle’s security system is functioning correctly and to avoid being stranded due to starting issues.

How to diagnose DTC P1629

To diagnose DTC P1629, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the P1629 code.
2. Check for any additional trouble codes that may provide more context.
3. Inspect the key or key fob for damage or wear.
4. Examine the wiring and connections related to the anti-theft system for any signs of damage or corrosion.
5. Test the anti-theft module and ignition switch for proper operation.
6. Verify that the ECM is functioning correctly and that its software is up to date.

How to fix DTC P1629 step-by-step instructions

To fix DTC P1629, follow these steps:

1. Replace or reprogram the key or key fob if it is found to be faulty.
2. Repair or replace any damaged wiring or connectors related to the anti-theft system.
3. Test and replace the anti-theft module if it is malfunctioning.
4. Check and replace the ignition switch if it is not functioning properly.
5. Update or reflash the ECM software if necessary.
6. Clear the DTC using an OBD-II scanner and test the vehicle to ensure the issue is resolved.

How to erase DTC P1629

To erase DTC P1629, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn the ignition key to the “On” position without starting the engine.
3. Access the scanner’s menu and select the option to clear or erase trouble codes.
4. Confirm the action and wait for the scanner to complete the process.
5. Disconnect the scanner and start the vehicle to check if the code reappears.

Recommended tools for OBD-II diagnostics

Explore our expert picks: The Best OBD2 Scanners for 2025

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.