What Does B2595 Mean?
This code indicates the Body Control Module (BCM) has detected a fault in the anti-theft system input signal circuit. The BCM is not receiving a valid or expected signal from one or more anti-theft system components, such as the transponder key sensor, immobilizer antenna ring, or related wiring. This fault prevents proper authentication of the ignition key and may result in a no-start condition or security system malfunction.
Safety Warning
Vehicle may not start or may start and immediately shut down due to immobilizer activation, leaving you stranded. While not a direct safety hazard if the vehicle runs, a no-start condition requires immediate attention to restore vehicle operability.
Common Causes
35%
Faulty transponder key or damaged key chip causing weak or no signal transmission to the immobilizer antenna
30%
Damaged or corroded wiring harness, connectors, or terminals in the anti-theft input circuit between the antenna ring and BCM
20%
Failed immobilizer antenna ring (transponder coil) around the ignition lock cylinder
15%
Body Control Module (BCM) internal fault or corrupted anti-theft programming
Diagnostic Steps
1
Verify the transponder key is the correct programmed key for the vehicle and check for physical damage to the key head or chip; test with a known good spare key if available to isolate key-related faults
2
Perform visual inspection of the immobilizer antenna ring around the ignition cylinder and its connector for physical damage, corrosion, or loose connections; wiggle test the connector while monitoring live data for intermittent signal loss
3
Using a digital multimeter, test for proper voltage supply and ground at the immobilizer antenna ring connector per manufacturer specifications (typically 5V or 12V reference); check for continuity in all wiring between the antenna ring and BCM connector pins
4
Monitor anti-theft system live data on the scan tool while inserting and turning the key to the ON position; verify the BCM receives a valid transponder ID signal and compare to expected values
5
If all circuits test normal, test the immobilizer antenna ring resistance with an ohmmeter (typical range 2-8 ohms); replace if out of specification or if insulation breakdown is detected
6
If all components and wiring test normal, verify BCM software is current and consider BCM replacement or reprogramming; after repairs, perform key relearn procedure and verify proper anti-theft system operation with multiple key cycles
Estimated Repair Cost
$100 - $800
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected a fault in the anti-theft system input signal circuit. The BCM is not receiving a valid or expected signal from one or more anti-theft system components, such as the transponder key sensor, immobilizer antenna ring, or related wiring. Th...
The most common cause of B2595 (Anti Theft Input Signal Circuit Failure) is: Faulty transponder key or damaged key chip causing weak or no signal transmission to the immobilizer antenna
Typical repair costs for B2595 range from $100 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may not start or may start and immediately shut down due to immobilizer activation, leaving you stranded. While not a direct safety hazard if the vehicle runs, a no-start condition requires immediate attention to restore vehicle operability.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2595 to identify the root cause.
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Quick Info
Category
Body
System
Anti-Theft/Security System
Difficulty
Type
Generic (SAE)
Recommended Tools
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