P0DA9: Hybrid/EV Battery Voltage/Drive Motor B Inverter Voltage Correlation
Do not keep driving
Expect reduced power, and probably no all-wheel drive. Mention any recent high-voltage or battery work. If the car has stored a matching code for the other motor, say so — the pair narrows the fault considerably.
What this code means
The pack voltage and the voltage measured at drive motor B's inverter do not agree.
Two instruments measure what sounds like one voltage, in two places, and this code is the comparison between them.
The battery management system measures at the pack. The inverter measures at the far end of the high-voltage cables, past the contactors, the fuse, the service disconnect and every bolted joint in between. In a healthy car those readings agree within a volt or two.
When they disagree, the fault is in the path between them — and that is a fault neither sensor could have found alone. A contactor whose faces have pitted, a bus bar bolt that was never torqued after a pack repair, a corroded joint: each adds resistance, and resistance under load produces a voltage drop that shows up as exactly this disagreement.
It is worth acting on sooner than the symptoms suggest, because the mechanism is a runaway. A resistive high-current joint heats, heat oxidises it further, and the resistance climbs. That is how pack connections end up melted rather than merely loose.
The alternative explanation is that one of the two sensors is lying, which is why the individual circuit codes should be read first — if either has stored one, that is the answer and this code is a consequence.
Because this names the second motor, comparing it against P0DA8 localises the fault for free. Both stored means the problem is upstream — shared cabling, a contactor, the pack itself. Only this one stored means it is in the branch feeding the second inverter, which is a much shorter length of car to inspect.
Likely causes
Start here
- Corroded or loose connector · specialist
- Damaged high voltage cable insulation · specialist
Less common
- Faulty battery pack sensor module · specialist
- Faulty power inverter · specialist
- Welded battery contactor · 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
Be the first to write this up
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.
Sign in or create an account to add what you found about P0DA9.