U0313: Software Incompatibility With Battery Energy Control Module B
What to do
Everything at U0312 applies: do not work around this, do not have it cleared, and do not attempt anything yourself. Expect the car to refuse to charge or to deliver power, and treat that as protection.
What is different here is that your battery is managed in sections, each with its own computer watching its own cells — which is how a pack of several hundred cells is monitored at all.
And that makes this particular mismatch worth taking seriously. Two computers managing the same battery to different rules is not a half-working system. The car is being told about its own battery in two different languages, and it cannot work out from the inside which is right. Refusing to charge is the only safe answer.
One thing worth mentioning if it applies: has part of the battery pack been replaced? That is a very common route into this. A replacement section arrives with its own computer at whatever software level it was built or stored at — so the job is not finished when the hardware is fitted. Every management computer in the pack has to be brought to the same calibration, and if that step was missed, this is the result.
This needs the manufacturer's own current software and a workshop equipped for high-voltage work.
What this code means
A second battery energy control module is running software that does not belong with its partners'. Everything at U0312 applies unchanged, including why this is the one place in the corpus where a matching part number is a safety matter rather than an economy.
What a second module means is the useful addition, because it changes what a mismatch implies.
Large packs are managed in sections. A module per module-group, per string, or per physical sub-pack, each measuring its own cells and reporting upward — which is how a pack of several hundred cells is monitored at all, and how a fault can be localised to a group rather than to the whole battery.
Which makes the specific danger of a mismatch between them worth stating: two managers of the same pack applying different limits. A section governed by one set of rules and another section by a different set is not a partially working system. It is a pack whose overall state is being computed from measurements that do not mean the same thing, and the vehicle cannot resolve that from the inside.
So the response is the same as at U0312 — refuse to charge, refuse to deliver — and it should be read the same way.
One practical consequence follows for repairs. A pack that has had a section replaced after a fault is a common route into this code, because the replacement section arrives with its own management module at whatever software level it was built or stored at. A section replacement is therefore not finished when the hardware is in: every management module on the pack has to be brought to one calibration, and that step is the job rather than an afterthought.
Likely causes
Start here
- Second hand module locked to another vehicle · specialist
- Incorrect module configuration after replacement · specialist
- Software updated on one module only · specialist
Less common
- Module replaced with one from another vehicle · specialist
- Interrupted module programming · specialist
- Software calibration out of date · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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