What it means
The vehicle bus reports loss of communication with smart HV battery pack coolant pump B. Active battery cooling cannot be commanded; charging/discharging power may be limited.
At a glance
- Usually lights the warning light of the system that lost communication
- The engine or gearbox may go into limp mode
How it works
Battery coolant pump B circulates coolant for the hybrid or electric vehicle’s high-voltage battery when that pump is called for by the thermal-management system. This code sets when the network stops receiving messages from pump B, so battery cooling may be unavailable and charging or driving power may be restricted.
Common causes
Most likely first.
- Bus wiring open or shorted
- Module without power or ground
- Module failed
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Record freeze-frame data and scan hybrid or EV modules for related communication, pump, and battery-temperature codes.
- Check live data for pump B’s communication status, battery temperature, and any available pump command or feedback.
- With the vehicle powered down according to its service instructions, inspect pump B’s connector and bus wiring for corrosion, looseness, or physical damage.
- Check that pump B has its specified low-voltage power and ground, since loss of either can silence its module.
- Test pump B’s communication wiring for an open or short using the wiring diagram and manufacturer procedures.
- If the bus circuit and supply are sound, determine whether pump B’s control electronics have failed.
Common fixes
- Reconnect or clean a loose or corroded pump B connector.
- Repair damaged or shorted communication wiring to pump B.
- Restore the pump module’s power or ground.
- Replace battery coolant pump B if its circuit and supply are sound and the module is faulty.
Can I keep driving?
Limit driving and avoid high-power charging until the fault is checked, especially if battery-temperature or power-limit warnings appear. Without pump B communication, the vehicle may restrict output and battery cooling may be compromised.
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.