2001 Prius. Codes 3001, 3019, 3125

Briefly (and I don't have deeper knowledge)
3001 battery ECU
3019 unknown
3125 converter/inverter assembly malfunction

The last one, at least, is an unwelcome addition to the list. The may be a wiring or connector problem, or it may be something expensive inside. There are subcodes for this (that many readers cannot detect) that might be useful in diagnosis.

Can you confirm the 3019 # is correct?

 

Hi tochatihu,

P3019 refers to Battery Block 9 Malfunction (Battery internal resistance is abnormal). There are 19 blocks of battery; P3011 being block 1, P3012 being block 2,...., P3029 being block 19.

Hi wenter,

Pls chk the connection of Block 9 especially the sense wire.

 

The code P3019 is one of those cases where reading out the minimum and maximum voltage and corresponding block number helps confirm the diagnosis. Do you have a way to read out the min/max voltage and module?

If you do, you could use the wheel blocked, "R", to force discharge the traction battery and then force charge in "D" while monitoring the minimum and maximum module voltage and their corresponding modules. This works with the engine warmed up. A high resistance module-pair will show up on both the charge and discharge cycle.

The P3125 is a generic inverter error and the subcode is the key to understanding the failure. Vincent1449p, have you had any luck getting SG to read subcodes for the inverter?

A basic requirement is to confirm the 12 V system measures ~13.8-13.9. We have seen problems in the past where the 12 V DC-DC converter failed leading to a low 12 V battery system and a host of other problem codes. If the inverter's 12 V system is running low or not charging that has to be fixed first.

Having rebuilt the battery with NHW20 modules, you could pull the battery and concentrate on the 9th pair. However, first make sure the 12 V system is OK (i.e., eliminate false codes.)

Bob Wilson

 

Hi Bob,

As far as I know, only the HV ECU store subcodes. If there is problem in the inverter, the HV ECU may log the subcodes. P3125 is one of them and I believe there should have subcodes.

Regarding the OP's problem, my suggestion is to ignore P3125 for now and check the battery connections first. The reason being those codes appear immediately after swapping the battery. Sometimes a problem in one area can generate codes in other area that is related but that doesn't mean there is really a problem in that area.

 

Thanks, this makes a lot of sense. I keep thinking of the manual listing 'subcodes' with the P3125 but the inverter is driven by the HV ECU.

Bob Wilson

 

Just wondering whatever happened here. Did the problem go away? I've also had p3019. After I pulled the code the check engine light went off and hasn't returned, and that was a month ago (~1200 miles)

 

Heat is the enemy and with the impending cold season, the car may run for sometime before the problem reoccurs. Also, keeping the car in service is likely to be better than say leaving it for a couple of weeks where the modules can self-discharge. But it is very likely the traction battery is weak and may need a replacement or rebuild. Planning makes it easier to deal with the problem.

Bob Wilson

 

That is true, thanks.