B2947 Code - Security System Sensor Power Circuit Low
Quick Answer
The Passlock™ system is provided in order to prevent vehicle theft if the ignition lock cylinder is forced to rotate or the ignition switch is operated while separated from the ignition lock cylinder case. Common causes include Faulty Security System Sensor, Security System Sensor harness is open or shorted, Security System Sensor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- B2947 indicates Security System Sensor Power Circuit Low.
- Common causes
- Common causes include Faulty Security System Sensor, Security System Sensor harness is open or shorted, Security System Sensor circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code B2947 Description
When the correct key is used to start the vehicle, a magnet on the lock cylinder passes close to the Passlock™ sensor within the ignition lock cylinder case. The magnet activates the security hall effect sensor in the Passlock™ sensor which completes a circuit from the security sensor signal circuit through a resistor to the security sensor low reference circuit. The resistance value will vary from vehicle to vehicle. The BCM will measure the voltage on the security sensor signal circuit and compare this voltage to a previously learned voltage. If the voltage measured is within the valid range, the BCM will send a class 2 message to the Powertrain Control Module (PCM) to enable vehicle starting. If the voltage measured is not within the valid range, a class 2 message will be sent to the PCM to disable starting of the vehicle.
What are the Possible Causes of the DTC B2947?
- Faulty Security System Sensor
- Security System Sensor harness is open or shorted
- Security System Sensor circuit poor electrical connection
- Faulty Body Control Module (BCM)
How to Fix the DTC B2947?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the B2947 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Information for Specific Makes
- B2947 Buick — Security System Sensor Power Circuit Low
- B2947 Cadillac — Security System Sensor Power Circuit Low
- B2947 Chevrolet — Security System Sensor Power Circuit Low
- B2947 GMC — Security System Sensor Power Circuit Low
Frequently Asked Questions about B2947 Code
1. What are the common symptoms of OBDII code B2947 (Security System Sensor Power Circuit Low)?
- Common symptoms include issues with the security system, such as the alarm not working properly or the vehicle not starting.
2. What are the possible causes of OBDII code B2947?
- Possible causes include a faulty security system sensor, damaged wiring or connectors, or issues with the security system module.
3. How can I diagnose OBDII code B2947?
- Diagnosing this code typically involves using a scan tool to read the code, checking the wiring and connectors for damage, and testing the security system sensor for proper functionality.
4. Can a DIYer repair OBDII code B2947 at home?
- Depending on the cause of the code, some DIY repairs may be possible, such as replacing a faulty sensor or repairing damaged wiring. However, more complex issues may require professional assistance.
5. Are there any tips for repairing OBDII code B2947?
- Tips for repairing this code may include checking and cleaning the sensor connections, ensuring proper voltage supply to the sensor, and following the manufacturer's diagnostic procedures.
6. How serious is OBDII code B2947?
- While this code may not always result in immediate drivability issues, it is important to address security system malfunctions promptly to prevent potential theft or starting problems.
7. Can OBDII code B2947 cause other problems in the vehicle?
- If left unresolved, this code can lead to security system failures, potential starting issues, and in some cases, the vehicle may go into an anti-theft mode preventing it from starting.
8. Is it safe to drive with OBDII code B2947 present?
- It is generally not recommended to drive with this code present, as it may indicate a security system issue that could compromise the safety and security of the vehicle.
9. How much does it cost to repair OBDII code B2947?
- The cost of repairing this code can vary depending on the underlying cause and whether the repair is done at a dealership, independent mechanic, or DIY. Costs may include parts and labor.
10. Can resetting the OBDII code B2947 resolve the issue temporarily?
- Resetting the code may temporarily clear the error, but if the underlying issue is not addressed, the code is likely to reappear. It is recommended to diagnose and repair the root cause of the problem.
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