P0B27 code meaning
Hybrid/EV Battery B Voltage
Powertrain system Generic code P0Bxx codes Check engine light
What P0B27 means
P0B27 is the general voltage fault of hybrid/EV battery B, the second separately monitored sub-battery or energy store. It covers a voltage that does not match expectation without saying whether it is unstable (P0B28), too low (P0B29) or too high (P0B2A). That battery B exists in production systems is shown by Stellantis, whose Jeep Wrangler 4xe bulletin lists P0B28; P0B27 itself is not documented publicly by any manufacturer. GM's analogous monitors of the whole pack are P0ABB to P0ABD, for example a pack reading more than 12 V away from the sum of the cells. CARB requires the voltage sensors and cells of hybrid storage systems to be monitored. The driver gets a hybrid warning and reduced battery power.
P0B27 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 10 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0B27
- Hybrid/EV system or high-voltage battery warning on
- MIL on
- Battery power limited, less electric drive or assist
- Charging or recuperation restricted
Common causes of P0B27
- PossibleWeak or failing cells or module in battery B
- PossibleFault in the voltage sense leads or connectors of battery B
- Less likelyBattery controller software or internal measurement fault
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery bBms
What each part of P0B27 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| B | Area: hybrid propulsion. |
| 27 | The exact fault in that area. |
What to do next
- Note P0B27 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0B27
What does P0B27 mean?
P0B27 means "Hybrid/EV Battery B Voltage". P0B27 is the general voltage fault of hybrid/EV battery B, the second separately monitored sub-battery or energy store. It is a generic code, so it means the same on every make.
Is it safe to drive with P0B27?
Drive gently and only to a workshop. With P0B27 the car can go into limp mode (reduced power) to protect itself.
Will P0B27 fail an emissions test?
Yes, it can. P0B27 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0B27 to fix?
Difficulty: workshop only. A typical repair takes 1 to 10 hours of work. This is a job for a workshop.
Will P0B27 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.