B1595 – Ignition Switch Illegal Input Code

The ODBII code B1595 indicates that the ignition switch has detected an illegal input, which may suggest a malfunction or improper signal from the ignition switch or related components.

The severity of ODBII code B1595 is moderate.

Common Causes For: B1594 Autolamp Delay Decrease Circuit Short To Ground

• Faulty ignition switch
• Wiring issues or damaged connectors
• Short circuit in the ignition circuit
• Faulty body control module (BCM)
• Corroded or loose electrical connections
• Malfunctioning key or key fob
• Software issues in the vehicle’s control modules

Common misdiagnosis for B1595 Ignition Switch Illegal Input Code

• Faulty ignition switch
• Wiring issues or shorts in the ignition circuit
• Malfunctioning body control module (BCM)
• Defective key or key fob
• Issues with the anti-theft system
• Faulty relays or fuses related to the ignition system
• Problems with the powertrain control module (PCM)

Common Troubleshooting Steps

The OBD-II code B1595 indicates an “Ignition Switch Illegal Input.” This code typically relates to issues with the ignition switch or its associated circuits. Here are some common troubleshooting steps to diagnose and resolve the issue:

• Check the Battery: Ensure that the vehicle’s battery is fully charged and in good condition. A weak battery can cause various electrical issues.
• Inspect the Ignition Switch:
• Check for any visible damage or wear on the ignition switch.
• Ensure that the ignition switch is properly connected and that there are no loose or corroded connections.
• Examine Wiring and Connectors:
• Inspect the wiring harness connected to the ignition switch for any signs of damage, fraying, or corrosion.
• Check the connectors for proper seating and any signs of corrosion or damage.
• Test the Ignition Switch:
• Use a multimeter to test the ignition switch for proper operation. Check for continuity in the different positions (OFF, ON, START).
• If the switch is faulty, it may need to be replaced.
• Check for Faulty Modules:
• Some vehicles have multiple control modules that may be affected by the ignition switch. Check for any fault codes in other modules that may provide additional insight.
• Inspect Fuses:
• Check the fuses related to the ignition system and other electrical components. Replace any blown fuses.
• Scan for Additional Codes:
• Use an OBD-II scanner to check for any other trouble codes that may be present. This can help identify if there are related issues.
• Clear Codes and Test Drive:
• After performing the necessary repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult Service Manual:
• Refer to the vehicle’s service manual for specific diagnostic procedures and specifications related to the ignition switch and associated systems.
• 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 B1595 code.