P3000: Battery Control System Malfunction
Toyota & Lexus “Messenger Code” — What the INFO Codes Tell You
✓ Toyota Prius, Camry Hybrid, Highlander Hybrid, Lexus hybrids
✓ The INFO code matters more than P3000 itself
✓ Mobile testing by DFW Hybrid Battery — we come to you
Quick Answer
Official definition: P3000 — “Battery Control System.”
What it really means: The battery computer reported a problem to the main hybrid computer. P3000 is the messenger, not the problem.
Most common on: Toyota and Lexus hybrids of the 2001–2009 era (Gen1 and Gen2 Prius, early Camry/Highlander Hybrids, Lexus RX 400h).
What to do: Read the INFO code and any other battery codes stored with it (often P0A80 or P3011–P3029) and diagnose those.
Can I keep driving?: Depends on the INFO code. Low-battery and fuse-related INFO codes can leave you stranded.
P3000 confuses a lot of owners — and some shops. Toyota’s own technical tip (T-TT-0303-14) is very clear: when the hybrid battery computer detects a fault, the hybrid control computer automatically stores P3000. Toyota tells technicians not to diagnose P3000 itself, but to diagnose the battery computer’s codes instead. The INFO number stored with P3000 tells you which direction to look.
P3000 INFO Codes
| INFO code | Meaning | Where to look |
|---|---|---|
| 123 | Abnormal signal from the battery ECU — HV battery system malfunction (source: Toyota repair manual) | Read the battery ECU codes — usually P0A80 and/or P3011–P3029 weak-block codes |
| 125 | Abnormal signal from the battery ECU — high-voltage fuse blown (Toyota repair manual) | The fuse inside the service plug / battery circuit, and why it blew |
| 388 | Discharge-inhibit control problem — the battery state of charge dropped too low (technician sources) | Running out of fuel, the car left in Neutral for a long time, or a failing battery/control system |
| 389 | Battery ECU detected a drop in battery voltage (technician sources) | Deeply discharged or weak battery, or a battery control fault |
| 603 | Abnormal signal from the battery ECU — HV battery cooling system malfunction (Toyota repair manual) | Battery cooling fan, fan circuit, temperature sensors |
Some websites list INFO 124 as the blown-fuse code; the Toyota repair-manual excerpt we reviewed shows 125. INFO 388 and 389 descriptions come from technician references rather than the manual pages we could verify, so we treat them as guidance and confirm on the car.
Situations That Commonly Set P3000
Running out of gas
If a Prius runs out of fuel, the hybrid system keeps using the battery until it is too low, which can set P3000 with INFO 388 or 389. Sometimes the battery recovers after refueling and a proper recharge; sometimes a weak pack is exposed.
Car left in Neutral
In Neutral the hybrid battery isn’t recharged by the engine. Leaving the car running in N for a long time can drain the pack and set P3000.
A weak battery block
The most common real-world combination is P3000 INFO 123 together with P0A80 and one or more P3011–P3029 codes (P3011–P3024 on 2004–2009 Prius), pointing to aging modules.
Cooling problems
INFO 603 points to the battery cooling system — a clogged or failed fan, or a fan circuit problem.
What Not to Do
- Don’t replace the hybrid control computer because P3000 is stored in it — Toyota specifically says P3000/123 does not indicate a fault in that computer.
- Don’t keep clearing the code and driving if INFO 388/389 appear; repeatedly draining a weak NiMH pack can make it worse.
- Don’t pull the service plug to “check the fuse” without high-voltage training and gloves.
How DFW Hybrid Battery Handles This Code
We read P3000 along with its INFO code and every code stored in the battery computer, check the pack’s state of charge and block voltages, and look at the cooling fan. If the cause was simply a drained pack, we’ll tell you — no need to sell a battery.
Frequently Asked Questions
Is P3000 a battery failure?
Not by itself. It tells you the battery computer reported something. The INFO code and the other stored codes tell you whether it’s the battery, the fuse, cooling, or a low state of charge.
My Prius ran out of gas and now shows P3000. Is the battery ruined?
Not necessarily. After refueling, the pack needs to be recharged and tested. A healthy pack often recovers; a pack that was already weak may not.
Does P3000 appear on newer Toyotas?
It is mainly seen on earlier Toyota and Lexus hybrids. Newer models use different code structures, such as seven-character codes like P1AC000.
Related Hybrid Codes
- P0A80 — replace hybrid battery pack
- P3011–P3029 — which block is weak
- Cooling codes — fan and temperature problems
- All hybrid battery error codes
Vehicle guides: Toyota Prius Gen 2 · Lexus RX400h & RX450h · All vehicles
Related services: Hybrid Battery Diagnostics · Repair & Reconditioning · Replacement · Warranty · Battery Charging · Prices · Areas We Serve
Sources & References
We base these guides on factory service bulletins, repair-manual information, and what we see in real repairs. Where a detail comes from technician forums or a parts seller rather than the manufacturer, we say so.
- Toyota T-TT-0303-14: P3000/123 Battery Control DTC Diagnostic Tips
- Toyota repair manual excerpt: P3000 INFO codes (2004 Prius)
- PriusChat technical discussion: P3000 INFO 388/389
P3000 on Your Toyota or Lexus?
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