B27B4 Code - Electric Compressor Low Voltage System
Quick Answer
The Diagnostic Trouble Code (DTC) sets when the voltage of battery power supply input to electric compressor is 9 V or less or 17 V or more. Common causes include Faulty Electric Compressor, Electric Compressor harness is open or shorted, Electric Compressor 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
- B27B4 indicates Electric Compressor Low Voltage System.
- Common causes
- Common causes include Faulty Electric Compressor, Electric Compressor harness is open or shorted, Electric Compressor 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 B27B4 Description
What are the Possible Causes of the DTC B27B4?
- Faulty Electric Compressor
- Electric Compressor harness is open or shorted
- Electric Compressor circuit poor electrical connection
- Faulty A/C Relay System
How to Fix the DTC B27B4?
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 B27B4 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
- B27B4 Infiniti — Electric Compressor Low Voltage System
- B27B4 Nissan — Electric Compressor Low Voltage System
Frequently Asked Questions about B27B4 Code
1. What does OBDII code B27B4 mean?
Code B27B4 indicates that the electric compressor in the vehicle is experiencing a low voltage condition in its supply or control circuit.
2. What are the common symptoms of code B27B4?
Symptoms may include reduced air conditioning performance, failure of the A/C system to cool the cabin, warning lights on the dashboard, or stored fault codes in the vehicle's control module.
3. What causes the B27B4 code to trigger?
The most common causes include a weak or failing battery, damaged wiring or connectors in the compressor circuit, a malfunctioning electric compressor, or issues with the power supply module.
4. Can I drive my car with the B27B4 code active?
While the vehicle can often still be driven, the air conditioning system may not function properly, and prolonged driving without addressing the issue could lead to further electrical problems.
5. How do I diagnose the B27B4 code?
Start by checking the battery voltage and condition, inspecting wiring and connectors connected to the electric compressor, and using a diagnostic scan tool to monitor the compressor's voltage levels.
6. How is the B27B4 code typically fixed?
Repairs may involve replacing damaged wiring, repairing or replacing the electric compressor, fixing loose connections, or addressing low battery voltage by replacing the battery or alternator if necessary.
7. Can a low battery cause the B27B4 code?
Yes, a weak or failing battery can cause insufficient voltage to the electric compressor, triggering the B27B4 code.
8. Does the B27B4 code always mean the electric compressor is faulty?
No, the code may also be caused by wiring issues, loose connections, or low system voltage rather than a direct fault in the compressor itself.
9. What tools are needed to troubleshoot the B27B4 code?
Common tools include a multimeter for checking voltage, a diagnostic scan tool for reading and clearing codes, and possibly a wiring diagram for tracing circuits related to the electric compressor.
10. How much does it cost to fix the B27B4 code?
Repair costs can vary widely depending on the root cause. Replacing a battery may cost $100–$300, while repairing wiring or replacing an electric compressor can range from $500–$1,500 or more.
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