B1605: Anti-Theft Indicator Circuit Short to Battery
The B1605 code indicates that the vehicle's control module has detected a short circuit to battery voltage (high voltage) in the anti-theft indicator light circuit. This circuit controls the operation of the PATS (Passive Anti-Theft System) indicator light, typically located on the instrument cluster. A short to battery means the signal wire is receiving constant power instead of the pulsed control from the module.
1. Commonly Affected Makes
2. Most Common Causes
- Wiring in the anti-theft indicator circuit shorted to positive power
- Anti-theft indicator light with internal short or damaged resistance
- Corroded or damaged connector or terminal at the indicator
- Faulty instrument cluster control module (ICM) or PATS module
- Aftermarket alarm system with incorrect wiring connections
3. Symptoms You Will Notice
- Anti-theft indicator light stays on constantly or does not function
- Engine may not start or PATS system may be inoperative
4. Step-by-Step Diagnosis
Check for technical service bulletins (TSBs) related to the vehicle
Visually inspect the anti-theft indicator circuit wiring and connectors for damage or corrosion
Test the indicator light circuit for short to battery voltage using a multimeter
Check the indicator light bulb or LED for internal short
If wiring and indicator are okay, test the instrument cluster and PATS module for faults
5. Frequently Asked Questions
Is it safe to drive?▼
The vehicle may be drivable, but the anti-theft system could malfunction, potentially causing the engine not to start. It is recommended to diagnose and repair the issue promptly.
How much does it cost to fix?▼
Repair costs typically range from $100 to $400, depending on the cause. Simple wiring repairs may be on the lower end, while replacing an instrument cluster or PATS module can be more expensive.