Hybrid Battery Voltage Sense Circuit Intermittent/Erratic
The P0B71 code indicates an intermittent or erratic signal from the hybrid battery voltage sense circuit. This circuit monitors the voltage of the high-voltage hybrid battery pack. An intermittent signal can be caused by loose or corroded connectors, damaged wiring, or a failing battery voltage sensor. This issue can lead to inaccurate battery state-of-charge readings, affecting hybrid system operation and potentially causing reduced fuel economy or loss of hybrid assist.
01. Most Common Causes
- Loose or corroded battery voltage sense connector
- Damaged or chafed wiring in the sense circuit
- Faulty hybrid battery voltage sensor
- Intermittent short or open in the circuit
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel economy
- Loss of hybrid assist or power
- Battery warning light on dashboard
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all codes and freeze frame data.
Step 2: Visually inspect the hybrid battery voltage sense connector and wiring for damage, corrosion, or loose connections.
Step 3: Perform a wiggle test on the wiring harness while monitoring the voltage signal with a multimeter or scan tool to identify intermittent faults.
Step 4: If no visible issues, test the battery voltage sensor per manufacturer specifications and replace if out of range.
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 can cause unpredictable hybrid system behavior and potential loss of power. Have it diagnosed promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and repair, depending on the cause and labor rates.