B1846 – Ignition Tamper Circuit Open

The ODBII code B1846 indicates a malfunction in the ignition tamper circuit, specifically that the circuit is open, which means there is a break in the electrical connection that monitors the ignition system for tampering.

The severity of ODBII code B1846 is moderate.

Common Causes For: B1845 Ignition Tamper Circuit Failure

• Faulty ignition switch
• Damaged wiring or connectors in the ignition circuit
• Open circuit due to a blown fuse
• Malfunctioning body control module (BCM)
• Poor ground connection
• Corroded or loose connections in the ignition tamper circuit

Common misdiagnosis for B1846 Ignition Tamper Circuit Open

• Faulty ignition switch
• Defective body control module (BCM)
• Wiring issues or shorts in the ignition circuit
• Malfunctioning key fob or transponder
• Issues with the anti-theft system
• Battery or power supply problems
• Faulty connectors or terminals in the ignition circuit

Common Troubleshooting Steps

The OBD-II code B1846 refers to an issue with the Ignition Tamper Circuit, indicating that there is an open circuit or a problem with the circuit that monitors the ignition system. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check the Vehicle’s Battery:
• Ensure that the battery is fully charged and in good condition. A weak or failing battery can cause various electrical issues.
• Inspect Fuses:
• Check the fuses related to the ignition system and the tamper circuit. Replace any blown fuses.
• Visual Inspection:
• Inspect the wiring and connectors associated with the ignition tamper circuit. Look for any signs of damage, corrosion, or loose connections.
• Test the Ignition Switch:
• The ignition switch can sometimes be the culprit. Test the ignition switch for proper operation and continuity. Replace it if necessary.
• Check for Ground Issues:
• Ensure that all ground connections related to the ignition system are secure and free of corrosion. A poor ground can lead to circuit issues.
• Scan for Additional Codes:
• Use an OBD-II scanner to check for any other related trouble codes that may provide more context to the issue.
• Inspect the Tamper Circuit Components:
• If applicable, check any components associated with the tamper circuit, such as relays or sensors, for proper operation.
• Perform a Continuity Test:
• Use a multimeter to perform a continuity test on the ignition tamper circuit. This will help identify any breaks in the wiring.
• Check for Short Circuits:
• Inspect the circuit for any short circuits that may be causing the open circuit condition.
• Consult Wiring Diagrams:
• Refer to the vehicle’s service manual for wiring diagrams to understand the circuit layout and identify potential problem areas. 1
• Reset the Code:
• After performing repairs, clear the trouble code using an OBD-II scanner and take the vehicle for a test drive to see if the code returns. 1
• Seek Professional Help:
• If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician for further diagnosis. By following these steps, you should be able to identify and resolve the issue related to the B1846 code.