Reading the codes before you buy a battery
A hybrid or EV dashboard warning is rarely a single fault. The codes below are the ones we see most often, and each one points to a different repair. Send us a scan screenshot and we will tell you whether you need a pack, a module, or something far cheaper.
P0A80 — Replace Hybrid Battery Pack
The generic “pack has failed” code. It means the battery ECU has seen block voltage spread beyond its limit. Usually one or two modules are weak rather than the whole pack — which is exactly why we quote module-level repairs as well as complete packs.
Read the full P0A80 diagnostic path →
P0A7F — Hybrid Battery Pack Deterioration
Capacity has dropped below the threshold the ECU expects for the vehicle’s age and mileage. Common on 2004–2015 Prius and Civic Hybrid packs. This is the code that usually precedes a genuine replacement.
Read the full P0A7F diagnostic path →
P0AC4 — Hybrid Powertrain Control Module Requested MIL
The hybrid control module is asking for the check-engine light. It is a messenger, not a diagnosis: read the stored sub-codes before assuming the battery is at fault.
Read the full P0AC4 diagnostic path →
P0A93 — Inverter “A” Cooling System Performance
Inverter overheating, normally a failing coolant pump or blocked duct rather than the inverter itself. We stock pumps, fans and complete inverters for Toyota, Lexus and Honda systems.
Read the full P0A93 diagnostic path →
P0A0D — High Voltage System Interlock
A safety interlock circuit has opened — often a service plug left unseated after a repair. Do not drive the car; the pack contactors are open and the vehicle may not start at all.
Read the full P0A0D diagnostic path →
P3000 — Battery Control System Malfunction
A generic block-level fault recorded by the battery ECU. Needs a live data read of block voltages to interpret; a parts cannon will not fix it.
Read the full P3000 diagnostic path →
How to send us a scan
Photograph or screenshot the freeze-frame data page showing all block voltages. With that we can usually tell you within a few hours whether you are looking at a module repair, a pack replacement, or a wiring fault.
Still not sure? The other 46 codes are in our handbook
This page only lists the most common codes. The full handbook covers every code we see in the workshop, with the voltages and module counts behind each one.
- 50+ fault codes: symptoms, common causes, self-check steps
- Block voltage and resistance thresholds (28 / 34 / 40-cell packs)
- Which codes can be fixed with one module — and which need a full pack
- PDF, sent to your inbox
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Reference
Prefer it as a document? Open the full fault-code handbook — every code, the diagnostic path and the replacement criteria in one place.