PATS Ignition Sensor Short to Ground
The powertrain control module (PCM) or body control module (BCM) has detected a short to ground in the ignition tamper sensor circuit, which is part of the passive anti-theft system (PATS). This fault prevents the module from reading the coded key correctly, disabling engine start as a security measure.
1. Commonly Affected Makes
2. Most Common Causes
- Damaged or internally shorted PATS transceiver ring
- Chafed or pinched wiring in the transceiver ring circuit contacting ground
- Corroded, loose, or bent pins in the transceiver ring connector
- Faulty ignition switch with internal short circuit
- Internal BCM/PCM failure in the circuit monitoring driver
3. Symptoms You Will Notice
- Engine cranks but does not start
- Security indicator light flashing or staying on
4. Step-by-Step Diagnosis
Scan for PATS-related DTCs and verify B1848 is present
Inspect the PATS transceiver ring and its wiring for damage, corrosion, or shorts to ground
Check the transceiver ring connector for bent or corroded pins
Test the transceiver ring resistance and compare to specifications
If wiring and ring are okay, suspect a faulty BCM or PCM
5. Frequently Asked Questions
Is it safe to drive?▼
No, the vehicle will not start due to the anti-theft system disabling the engine. Do not attempt to drive.
How much does it cost to fix?▼
Repair costs typically range from $150 to $600, depending on whether the issue is wiring, the transceiver ring, or a module replacement.