What Does B1600 Mean?
This code indicates the Passive Anti-Theft System (PATS) or immobilizer system failed to receive or recognize the transponder signal from the ignition key. The vehicle's anti-theft control module detected that the encrypted chip embedded in the key did not communicate properly with the transponder receiver around the ignition cylinder. This prevents the vehicle from starting as a security measure, ensuring only programmed keys can operate the vehicle.
Safety Warning
Vehicle will not start due to anti-theft lockout, rendering it immobile but posing no direct safety risk while stationary. This is a security feature working as designed when transponder communication fails. Immediate repair is necessary to restore vehicle operation.
Common Causes
35%
Faulty or damaged ignition key transponder chip or unprogrammed/wrong key being used
30%
Failed transponder receiver antenna ring around ignition cylinder
20%
Wiring harness damage or connector corrosion between transponder antenna and anti-theft module
10%
Failed anti-theft control module or powertrain control module communication fault
5%
Low battery voltage or electrical interference affecting transponder signal transmission
Diagnostic Steps
1
Step 1: Attempt to start the vehicle with all available keys to determine if the issue is key-specific or system-wide. Document which keys trigger the no-start condition and observe if security indicator light flashes rapidly during crank attempt.
2
Step 2: Measure battery voltage at rest (should be 12.4-12.6V) and during crank attempt (should not drop below 9.5V). Low voltage can prevent proper transponder communication and cause false PATS faults.
3
Step 3: Visually inspect the transponder antenna ring around the ignition cylinder for physical damage, proper seating, and secure connector attachment. Check connector pins for corrosion, bent terminals, or moisture intrusion.
4
Step 4: Using a multimeter, test continuity and resistance on the wiring harness between the transponder antenna ring connector and the anti-theft module connector per manufacturer specifications (typically 3-8 ohms for antenna coil resistance).
5
Step 5: Access live data through the scan tool to monitor transponder signal status, key ID recognition, and anti-theft module communication with PCM during key-on attempts. Verify the module is detecting key insertion events.
6
Step 6: If all previous tests pass, attempt to reprogram existing keys or program a new key using manufacturer-specific procedures through the scan tool or dedicated programming equipment to verify anti-theft module functionality.
Estimated Repair Cost
$100 - $600
Parts + labor, varies by vehicle and location
This code indicates the Passive Anti-Theft System (PATS) or immobilizer system failed to receive or recognize the transponder signal from the ignition key. The vehicle's anti-theft control module detected that the encrypted chip embedded in the key did not communicate properly with the transponder r...
The most common cause of B1600 (PATS Ignition Key Transponder Signal Is Not Received) is: Faulty or damaged ignition key transponder chip or unprogrammed/wrong key being used
Typical repair costs for B1600 range from $100 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle will not start due to anti-theft lockout, rendering it immobile but posing no direct safety risk while stationary. This is a security feature working as designed when transponder communication fails. Immediate repair is necessary to restore vehicle operation.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1600 to identify the root cause.
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Quick Info
Category
Body
System
Anti-Theft/Security System
Difficulty
Type
Manufacturer
Recommended Tools
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