B1682
PATS Is Disabled (Check Link Between PATS And Transponder)
Body Chassis/Safety Keyless/Anti-Theft 🟢 Low — Fix at next service
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What This Actually Means
In plain language — no jargon

Your car's security system (PATS) can't communicate with your key's transponder chip, like a lock that can't read your key's unique pattern. The vehicle won't start because it can't verify the key is authentic.

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Symptoms You May Notice
3 known symptoms for this code
Engine will not start or crank
Security/PATS warning light illuminated on dashboard
Key fob or transponder not being recognized by vehicle
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Embedded Systems Insight
What the ECU/ECM is actually computing

The PATS module sends a signal to the transponder in the key and expects a valid coded response back within a specific time window. If no response or an invalid code is received, the ECU disables fuel injection and ignition to prevent unauthorized starting. The system monitors signal strength and response integrity.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Transponder Response Signal Valid coded signal received within 100-200ms No response, weak signal, or invalid code detected
PATS Module Communication Link Active two-way communication established Communication timeout or link failure
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Key battery
Replace the battery in your key fob to ensure the transponder has power to transmit its signal.
2
Key/transponder contacts
Clean the metal contacts on both the key and the ignition cylinder with a dry cloth to improve signal transmission.
3
PATS antenna wiring
Inspect wiring around the steering column and ignition switch for corrosion or loose connectors and reseat connections firmly.