P0B90 code meaning
Hybrid/EV Battery Voltage Sense R Circuit
Powertrain system Generic code P0Bxx codes Check engine light
What P0B90 means
P0B90 is stored when the battery controller concludes that the tap of sense R, the eighteenth cell channel, is open or too resistive. GM's 2019 battery energy control module runs seven cases for it: neighbouring cells 1.3 V or more apart, a reading under 36 mV while the balancing gate is on, or splice voltages above 0.1 V (0.5 V at a busbar splice). The fault has to be present for 0.8 s within a 1.6 s window and is Type A. The 2016 Volt and ELR use the same cases with a 0.6 s window. Oddly, GM's first-generation Volt tables of 2011 to 2015 contain no P0B90 at all, although they list the circuit codes of S to V. Range, low and high faults of R are P0B91 to P0B93.
P0B90 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 P0B90
- MIL with service hybrid or EV system warning
- Reduced propulsion power or no ready mode
- Charging interrupted or refused
Common causes of P0B90
- Most likelyLoose, corroded or broken tap of sense lead R
- PossibleExcessive resistance at a splice or busbar joint feeding channel R
- Less likelyFaulty measuring or balancing input on the cell monitoring board
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery voltage sense rWiring harnessBms
What each part of P0B90 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. |
| 90 | The exact fault in that area. |
What to do next
- Note P0B90 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 P0B90
What does P0B90 mean?
P0B90 means "Hybrid/EV Battery Voltage Sense R Circuit". P0B90 is stored when the battery controller concludes that the tap of sense R, the eighteenth cell channel, is open or too resistive. It is a generic code, so it means the same on every make.
Is it safe to drive with P0B90?
Drive gently and only to a workshop. With P0B90 the car can go into limp mode (reduced power) to protect itself.
Will P0B90 fail an emissions test?
Yes, it can. P0B90 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 P0B90 to fix?
Difficulty: workshop only. A typical repair takes 1 to 10 hours of work. This is a job for a workshop.
Will P0B90 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.