Code
B1682
Other
B — Body
PATS Is Disabled (Check Link Between PATS And Transponder)
AI status
Completed
Completed
100%
Causes
- PATS/immobilizer module disabled or software flag set
- Transponder key not recognized or damaged
- Antenna coil (ignition barrel reader) fault or poor connection
- Power, ground, or blown fuse to PATS module
- Wiring harness or connector corrosion/shorts between PATS and key reader
- CAN/LIN communication error between PATS, BCM and PCM
Symptoms
- Security warning or immobilizer indicator illuminated on dash
- Engine cranks but will not start, or no-crank condition depending on vehicle
- Intermittent starting failures tied to specific keys
- No recognition of transponder when key inserted/within reader range
- DTCs present related to immobilizer/PATS and communication errors
What to check
- Scan vehicle and confirm B1682 plus any other related DTCs in PATS/BCM/PCM
- Verify battery voltage is within 11–14 V during testing
- Observe immobilizer/security indicator behavior during key insertion/attempted start
- Try a known-good spare/key that is already programmed to the vehicle
- Inspect fuses and power/ground at PATS/immobilizer module and antenna ring
- Visually inspect connectors and wiring for corrosion, pin damage or loose terminals
Signal parameters
- PATS module supply voltage: expected ~11–14 V
- Ground continuity to PATS module: good reference to chassis
- Transponder ID / Key code reported by PATS (present or blank)
- Key valid flag: true/false in scan-tool live data
- Antenna coil resistance/continuity per manufacturer spec
- Antenna coil signal strength or tag detect event when key is inserted
Diagnostic algorithm
- Confirm code: Use a capable scan tool to read B1682 and note any associated codes in PATS, BCM, or PCM.
- Reproduce symptom: Observe security lamp and attempt start with the reported key and any spare keys.
- Verify power/ground: Measure supply voltage and ground at the PATS module and antenna ring; repair any fuse or power faults.
- Inspect wiring/connectors: Repair corroded or damaged connectors between ignition/antenna and PATS module.
- Test antenna ring/reader: Check continuity/resistance and watch live data or oscilloscope while inserting key to confirm transponder detection.
- Test with known good key: If spare programmed key starts vehicle, suspect primary key transponder failure or key programming issue.
- Check communications: Use scan tool to view CAN/LIN data between modules; address any bus faults first.
- Attempt re-learn: If hardware is OK, follow factory key reprogram/learn procedure to re-enable PATS and relearn keys. Clear codes and retest.
- Module software/hardware: If PATS module will not enable or learn keys after correct procedures, consider module replacement or reflashing per factory guidance.
- Final verification: After repairs/programming, erase codes, verify successful starts with all vehicle keys, and confirm no recurrence.
Likely causes
- Faulty or unprogrammed transponder key
- Failed antenna ring or poor continuity at ignition cylinder
- Intermittent power/ground to PATS module (battery disconnected recently)
- Connector corrosion or damaged wiring at PATS or ignition switch
- Module software/firmware fault or unexpected module replacement without reprogramming
Fault status
Status
PATS disabled — immobilizer and transponder link not established. Vehicle may not start until PATS and key are linked or faulty components repaired.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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