P0AC4 on 2019-2022 Toyota RAV4 — Hybrid Powertrain Control Module Requested MIL Illumination
1 vehicles · 1 makes
Most Reported On
P0AC4 is an OBD-II diagnostic trouble code meaning “Hybrid Powertrain Control Module Requested MIL Illumination.” The hybrid powertrain control module has requested the malfunction indicator lamp be turned on due to a stored internal/hybrid system fault. This code is most commonly reported on 2019-2022 Toyota RAV4.
Common Causes
Diagnostic Tools
This is a powertrain code, so a basic OBD-II reader can read it. These read P0AC4.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple code reader for engine (P) codes on many compatible OBD-II vehicles. It does not support every vehicle or hybrid/EV application, and it does NOT read body, chassis or network codes; confirm exact-vehicle compatibility before buying.
- Read & clear engine (P) codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth scanner with a companion app that reads beyond the engine module — ABS, SRS and transmission — plus manufacturer-specific codes on many vehicles.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X V3.0 Elite OBD-II Scanner
by LAUNCH
Handheld scanner covering the four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level tablet with all-system coverage and bi-directional control, so you can command a module rather than only read it.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
What you can do yourself, and what needs a shop
Reading the code, clearing it, and watching whether it returns is a driveway job with the right scanner. These steps are not:
- Module programming or software updates — needs the manufacturer software or a J2534 pass-through with a paid subscription.
- Replacing a control module — most are VIN-programmed and immobilizer-registered, so a new one does nothing until it is coded to your car.
- Airbag/SRS component work — a stored fault can deploy a live device.
If the vehicle is still under warranty, check for an open recall or technical service bulletin before buying anything — the repair may already be covered.
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FAQ
What does P0AC4 mean?
P0AC4 stands for "Hybrid Powertrain Control Module Requested MIL Illumination." The hybrid powertrain control module has requested the malfunction indicator lamp be turned on due to a stored internal/hybrid system fault.
What are the most common causes of P0AC4?
The most common causes of P0AC4 are: Internal hybrid powertrain control module fault, Stored hybrid system DTC requiring MIL, Communication/wiring fault, Module power/ground issue. The specific cause varies by vehicle.
How much does it cost to fix P0AC4?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by P0AC4?
Au7o has documented P0AC4 across 1 vehicle models from 1 manufacturers: Toyota.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.