Hybrid Battery Voltage Sense Circuit Intermittent/Erratic
The P0B85 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 fault can be caused by loose connections, damaged wiring, or a failing battery voltage sensor. This issue may lead to inaccurate battery state-of-charge readings, reduced fuel economy, or in some cases, the hybrid system may shut down to protect the battery.
01. Most Common Causes
- Loose or corroded battery voltage sense wire connections
- Damaged or chafed wiring in the voltage sense circuit
- Faulty hybrid battery voltage sensor
- Intermittent open or short in the circuit
02. Symptoms You Will Notice
- Check Engine Light or Hybrid System Warning Light on
- Reduced fuel economy or decreased hybrid system performance
- Inaccurate battery charge level display
- Possible hybrid system shutdown or limp mode
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 sense wiring and connectors for damage, corrosion, or looseness.
Step 3: Perform a wiggle test on the wiring harness while monitoring the voltage signal with a multimeter or scan tool to identify intermittent breaks.
Step 4: Check the hybrid battery voltage sensor resistance and compare to manufacturer specifications; 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 inaccurate battery monitoring and may lead to hybrid system failure or reduced performance. Have the vehicle inspected promptly.
How much does it cost to fix?▼
The cost to diagnose and repair a P0B85 code typically ranges from $50 to $150 for diagnosis, plus parts and labor for any necessary repairs. Sensor replacement or wiring repair may add additional costs.