P1793 Ignition Supply Malfunction

• OBD2 Code: P1793
• Description: Ignition Supply Malfunction
• Definition: The P1793 code indicates a problem with the ignition supply voltage, which may affect the vehicle’s ability to start or run properly. This can be due to issues such as faulty wiring, a bad ignition switch, or problems with the powertrain control module (PCM).

P1793 – Ignition Supply Malfunction

Typical Severity: Severe

Common Causes

P1793 – Ignition Supply Malfunction

Common Causes:

• Faulty ignition switch
• Blown fuse related to the ignition system
• Wiring issues in the ignition circuit
• Defective ignition relay

 

Common Misdiagnosis

OBD2 Code: P1793

Description: Ignition Supply Malfunction

Common Misdiagnosis: Replacing the ignition switch without checking for wiring issues or blown fuses.

 

Common Diagnostic Steps

OBD2 Code: P1793

Description: Ignition Supply Malfunction

• Check the battery voltage and connections to ensure they are secure and free of corrosion.
• Inspect the ignition switch for proper operation and signs of wear or damage.
• Examine all related fuses and relays for continuity and proper function.
• Test the ignition coil(s) for correct resistance values using a multimeter.
• Verify that the wiring harnesses connected to the ignition system components are intact, without any frayed wires or loose connections.
• Use an OBD2 scanner to clear the code, then perform a test drive to see if it returns, indicating an intermittent issue.
• If equipped, check for any Technical Service Bulletins (TSBs) related to this code for your specific vehicle model.