P3004 after replacing hybrid battery modules

Hello, priuschat. The battery modules in my HV battery were getting weak. As a precaution I drained my HV battery. My discharger was damaged so I did this by putting it in neutral. I then pulled the HV battery pack out and replaced all modules with 2017 prius modules. I also used brand new bus bars. According to what I see in doctor prius app (attached), I think the install went well except for the p3004. It's looking like an inverter issue since the 12V battery isn't charging now. I checked all the fuses and they were Ok. Is there anything else I should look for? Thanks!

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Almost forgot to mention that it won't go into reverse or drive. And the engine won't start in maintenance mode...



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I followed ChrisFix's instructions from this video:

All harnesses were reconnected. I can hear the relays click when I try to start the vehicle.

I don't have Techstream working at the moment.

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Thanks for the reminders, this is what I need.

Since the relays are clicking, first I'll focus on testing the power output wires - make sure they are all connected. I'll then attach a multimeter to the frame wires (main power) at the junction block connections using alligator clips. I'll then have an assistant attempt to start the car while I watch voltages.

If that doesn't help, I'll disconnect each connector, check for bent and pushed out pins, clean all pins with contact cleaner, dry, and then reconnect.

 

I put a voltmeter on the frame wires. When I push the start button with brake pedal pressed I hear two audible clicks and the voltage does a slight bounce but stays well under 1 V.

I'm suspecting at least one relay is old and malfunctioning. It probably is stuck after flipping the battery pack assembly. No idea how to remove them from the junction box for testing? Can I tap them with a mallet or something to try and loosen them up?

The connectors and pins look fine. I sprayed them with contact cleaner.

 

I have an appointment with the dealership in a couple of weeks and want to rule out any non-inverter failures with the car before I tow ($$) it to Toyota for diagnosis ($$). Just because I like to fix simple things myself and save money.

From my test results so far, the preload relay is only sending millivolts to the frame wires or maybe one of the inverter or frame wires is shorted. I checked the preload resistor and it was 31 ohms (within spec).

Thinking about a few more tests:

1. Disconnect the frame wires from the junction box. Check the junction box output resistance while relays are off. Manual says it should be around 20k Ohms.

2. Disconnect frame wires and HV battery cables to junction block. Apply ground to junction box and battery voltage to the junction box control pin. Check that relays turn on and drop the resistance of the frame wire terminals. I'd need to know the terminal type of the control pin or buy a kit with assortment of pins.

3. Disconnect frame wires from inverter. Check resistance across inverter frame wire terminals. Anyone know the resistance specs for that? I'm assuming should be at least a few ohms.

4. Disconnect frame wires at both ends. Measure - frame wire resistance to chassis ground. Should be open circuit.
5. Same test with + frame wire.

The junction box relays are stuck in their own caskets with no surfaces for pulling them out by hand.
If anyone knows how to remove the relays non-destructively from the junction box - it would be amazing if you'd share. It'd be way easier to test the relays directly.

Any other thoughts or advice?

 

Thanks @ChapmanF. You're right there are diagnostic instructions for all the P3004 codes. I was able to download a bunch of them from TIS.

Following the diagnostic steps for P3004-131 I found something. In the attached test, connector k2 does not register a voltage. I'm thinking this means the HV ground is disconnected somehow. All the cables are hooked up AFAICT.

I'll rewatch the Chrisfix video. Hopefully I'll find something. If someone has suggestions I'd appreciate it.

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View attachment 257151

 

I figured it out.

The ground lug for the battery was stuck underneath a module compressor plate. So I didn't realize it wasn't connected.

Thankfully I didn't need to remove the pack. Removing the terminal block, bracket and a few connectors I was able to maneuver the ground cable out.

This is the first time I've disassembled the HV battery pack. I learned much.


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An update: The car drives but with a P0A80. All HV modules look great except for module #10 as evidenced by a Dr Prius log. What happens is the SOC number shown will suddenly drop from 60% down to 25%. Only #10 falls 2V lower than all others and looks like it needs more high voltage balancing.

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All codes are gone and the Prius drives better than new!

Thanks to everyone who nudged me in the right direction.

Some pictures.

Old battery in Dr Prius app:



Ground wire causing P3004:


Charging the almost new modules out of a 2017 Prius. I stored them for 2 years @ 0.6V per cell:

Repaired battery assembly: