Mysterious Engine Problems

Buy one of these and keep it in your glovebox: Hybrid battery diagnostic and repair tool for Toyota and Lexus

Whenever the triangle comes on you can use Dr. Prius app on your phone to read the error codes and clear the triangle and keep driving...

Once you know the error codes we can give you a range of repair options depending on what you can afford....

While waiting for the device to arrive you can disconnect your 12v battery for a few minutes to clear the red triangle. How long it takes to come back on will define how urgent the problem is.

 

While waiting for your OBD2 bluetooth/wifi adapter that was kindly mentioned by @PriusCamper , you might try retrieving the stored OBD2 codes (DTCs) by visiting one of the auto part chain stores (autozone, pepboys, carquest, AAP, o'reillys, etc) and asking for a free OBD2 scan of your vehicle. Be sure to try multiple locations even within the same chain, as not all chains/locations will have a toyota hybrid compatible OBD2 scanner, and may not be able to retrieve the stored codes. Once recorded, please post them here for additional guidance.

 

Even before going to such a store, you could get the codes from the brake ECU (the reasons for the (!) and VSC lights) and probably even the TPMS ECU, using the jumper wire and blink-counting method. Won't work for the HV ECU so you will still be wondering about the codes behind the master warning triangle until there is a code reader handy.

But because the ECUs talk to each other, often even finding out what the codes are in the brake ECU will give a hint or two about the codes elsewhere.

 

Hybrid battery has failed its in limp mode.

Use the search forum link up top and search

hybrid battery

and read the hundreds of posts about failed hybrid battery we have all been through.

 

And if you have any time left, you can read the trouble codes and see if that's what's wrong with your car.

 

I was driving on my normal way home and the friendly of’ triangle popped up (along with the (!) and VSC warning light but no check engine)! After like 20 minutes it went off,

The above symptoms are 100% not indicative of a P0A80 (replace hybrid battery) code. The triangle of death does not just "turn off" 20 minutes later for an HV battery failure/code. But it might for an over temp in the cooling system or a glitch in the brake system.

When I accelerate it’s normal but when I coast I can constantly hear a rubbing/rumbling sound which is most apparent and loud when I brake. The car feels like it’s stuck in B mode for sure.

That pretty much eliminates being in limp mode.


Best advice given was to get the codes read by a Prius speaking code reader.

 

Those codes are about a temperature sensor for MG2 in the tranny. There are wires from the sensor to the ECU. There are minor things worth checking before condemning the whole transaxle.

 

Yes... The disconnection of 12v will clear the codes until the car notices them again...

 

P0A2B=Drive Motor A temperature sensor circuit range/performance=motor temperature sensor #2 performance problem=possible trouble area is hybrid vehicle motor

P0A2C=Drive Motor A temperature sensor circuit low=Ground short in motor temperature sensor #1 circuit=possible trouble areas are hybrid vehicle motor, wire harness or connector, HV control ecu

Sounds like I would follow post 11 to start and look to see if the sensor circuit has a ground.

There are links in the forum for the online repair manual. It will provide the DTC guide for troubleshooting the code.

The link below will take you to a post that has the service manual link

help (code p0A1d) | PriusChat

 

These were not taken from the most recent repair manual, but will give you a general idea.

Here is the workup for DTC P0A2B with INFs 248 and 250 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/21bpm/0a2b248.pdf

Here is the workup for DTC P0A2C with INF 247 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/21bpm/0a2c247.pdf

Notice how each of the above DTCs have two (2) related INFs (aka subcodes), though not that helpful with these old workups, knowing the INF for an associated DTC may help save on labor, parts or unnecessary expense. Techstream (the same diagnostic software that the dealership technicians used, and then charged you 160 for their expert advice) can retrieve the three (3) digit INFs, if they exist for a particular DTC.

Here is the workup for DTC P3000 with INFs 123, 125, 603 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/21bpm/3000123.pdf

Here is the workup for DTC P3000 with INF 388 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/21bpm/3000388.pdf

Here is the workup for DTC P3000 with INF 389 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/21bpm/3000389.pdf

Did the dealer include any 3 digits INFs for the above DTCs?

Which part of CA are you near, maybe another member can offer help.

These last two questions below are for a data point to see if there is a pattern for failures.

Have you ever checked, or changed the ATF-WS in the transaxle assembly?

Do you live in a mountainous area, or find yourself depleting the HV battery state of charge while climbing hills at speed?