Hybrid Battery Voltage Sense Circuit Low
The P0B79 code indicates that the hybrid battery voltage sense circuit is reading a voltage lower than expected. This circuit monitors the voltage of the hybrid battery pack to ensure proper charging and discharging. A low voltage reading can be caused by a faulty battery voltage sensor, damaged wiring, or a weak hybrid battery. This condition may lead to reduced hybrid system performance and potential battery damage if not addressed.
01. Most Common Causes
- Faulty hybrid battery voltage sensor
- Damaged or corroded wiring/connectors in the voltage sense circuit
- Weak or failing hybrid battery pack
- Open or short circuit in the voltage sense circuit
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel economy
- Hybrid system warning light on
- Loss of hybrid power assist
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all stored codes and freeze frame data.
Step 2: Visually inspect the hybrid battery voltage sensor and its wiring for damage, corrosion, or loose connections.
Step 3: Measure the voltage at the sensor connector with a multimeter and compare to manufacturer specifications.
Step 4: Test the hybrid battery pack voltage and individual cell voltages to identify weak cells.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it may indicate a serious issue with the hybrid battery system. Continued driving could lead to battery damage or complete loss of hybrid function.
How much does it cost to fix?▼
The cost to fix P0B79 typically ranges from $50 to $150 for diagnosis and minor repairs like wiring fixes. However, if the hybrid battery needs replacement, costs can exceed $1,000.