B1845 – OBD-II DTC

OBD-II DTC B1845 – Ignition Tamper Circuit Failure

DTC B1845 meaning

DTC B1845 refers to an “Ignition Tamper Circuit Failure.” This diagnostic trouble code indicates that the vehicle’s onboard diagnostic system has detected an issue with the ignition tamper circuit, which is responsible for monitoring the integrity of the ignition system. This circuit is crucial for ensuring that the vehicle’s ignition system has not been tampered with, which could lead to unauthorized access or operation of the vehicle.

DTC B1845 symptoms

Common symptoms associated with DTC B1845 may include:

• Illumination of the check engine light or warning indicator on the dashboard.
• Difficulty starting the vehicle or intermittent starting issues.
• Loss of functionality in certain electrical components or systems.
• Potential security system alerts or malfunctions.

DTC B1845 causes

Several factors can lead to the triggering of DTC B1845, including:

• Faulty ignition tamper circuit wiring or connectors.
• Malfunctioning ignition switch.
• Issues with the vehicle’s body control module (BCM).
• Corrosion or damage in the ignition system components.
• Previous tampering or unauthorized modifications to the ignition system.

DTC B1845 seriousness

The seriousness of DTC B1845 can vary depending on the underlying cause. While it may not immediately affect the vehicle’s drivability, it can lead to:

• Increased risk of vehicle theft or unauthorized use.
• Potential for further electrical issues if left unaddressed.
• Inability to start the vehicle in some cases.

It is advisable to diagnose and resolve this issue promptly to ensure the vehicle’s security and functionality.

How to diagnose DTC B1845

To diagnose DTC B1845, follow these steps:

1. Use an OBD-II scanner to confirm the presence of DTC B1845.
2. Inspect the ignition tamper circuit wiring and connectors for damage or corrosion.
3. Check the ignition switch for proper operation.
4. Examine the body control module (BCM) for any faults or issues.
5. Clear the DTC and perform a test drive to see if the code reappears.

How to fix DTC B1845 step-by-step instructions

To fix DTC B1845, follow these step-by-step instructions:

1. Begin by inspecting the ignition tamper circuit wiring and connectors for any visible damage or corrosion.
2. If any issues are found, repair or replace the damaged wiring or connectors.
3. Test the ignition switch for proper functionality replace it if it is faulty.
4. Check the body control module (BCM) for any error codes or malfunctions
   

   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

   ← All OBD-II Diagnostic Trouble Codes

   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.