What it means
The BMS detects a circuit low fault on voltage sense channel R of the high-voltage battery. Cell-group voltage measurement is unreliable on this channel.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The high-voltage battery management system (BMS) uses channel R to measure a battery cell group and check its voltage. P0B92 sets when the channel R signal is lower than the BMS expects, so that group’s voltage reading cannot be trusted.
Common causes
Most likely first.
- Sense wire shorted to ground
- Open in sense wire
- Connector pins corroded - high contact resistance
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
How to diagnose it
- Save freeze-frame data and compare channel R with other battery voltage readings to see whether it is consistently low or the fault appeared under a particular operating condition.
- With the vehicle powered down as the manufacturer specifies, inspect channel R’s accessible wiring and connectors for damage, corrosion, or signs of contact with ground.
- Have a qualified hybrid technician check channel R’s connector seating and pin condition; high contact resistance can pull the sensed signal low.
- Test the channel R sense wire for an open or short to ground using the manufacturer's procedure and specification.
- If the wiring and connections pass, compare the BMS input and cell-group readings using the manufacturer's diagnostic procedure to determine whether module-level diagnosis is needed.
Common fixes
- Clean or repair corroded channel R connector pins and restore a secure connection.
- Repair damaged channel R wiring that is open or shorted to ground.
- Replace a damaged connector or terminal causing poor contact.
- Repair or replace the battery monitoring component only if testing confirms it is faulty.
Can I keep driving?
Avoid relying on electric power or attempting to charge the vehicle while the BMS cannot trust channel R; reduced power or limp mode may occur. Arrange prompt diagnosis, and stop in a safe place if power becomes inadequate for traffic.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.