New “Check hybrid system” during diagnostics and testing

3rd gen 2013 Prius @150k miles; Hard start was rumbling way worse than usual around 150k miles. Except during motorcycle season, the car is driven 5 days a week around 100 miles a day, round trip. Hit stop and go traffic on and off for typically about 25-50% of the way. Then drive short distances 5-10 miles through city traffic for errands.

Not maintained well; I’ll be honest.. I change the oil and brake pads, but never take the car in for a service or perform any other maintenance until it presents as a problem. What an awesome car to have lasted so long with no trouble..

As the rumble was presenting as a problem, shaking harder, lasting longer periods before stabilizing, and throwing codes P030x multiple misfires and 3 specific misfires intermittently, I pulled out the Haynes manual and the OBD manual, and started checking and replacing things.

New spark plugs (gapped to spec; number one plug visibly worn more than the other 3 after only a few hundred miles); all new ignition coils; removed and cleaned EGR cooler and routing; can hear all 4 injectors firing at the same rate; battery voltage just above 12 volts; new PCV valve; removed and cleaned intake manifold and passage ways; new air filter; removed and cleaned throttle body; performed fuel pressure test and everything was up to specs; removed and inspected fuel pump for depths or anything abnormal looking.

The fuel pump was where something went wrong, I suspect.. The manual says to test fuel pump electrical by hooking up a 12 volt battery. I realized later that I connected to the wrong contacts in the connector.. but as soon as I connected to the battery, I didn’t hear any noise from the pump so I immediately disconnected. I could feel the heat in my leads.. I felt unsure about that test after that.. so I moved on. I disconnected the exterior connector, removed fuel pump, and disconnected the interior pump electrical connector (blue and black wires only, did not disconnect fuel level arm connector). Everything looked nice and clean as far as I could tell.. so I put it back together, reinstalled it into the tank, and sprayed the exterior connectors with electrical contact cleaner. I let it dry for about 5 minutes, but I think there may have been some left inside when I reconnected.

Reconnected battery, started car, “check hybrid system” appeared on display, and had no fuel pressure.

Removed integration module, removed the cover, and starting poking around for continuity. Found the blue and black wires to the fuel pump and found continuity. On the common incoming connection (from the PCM?) there were 2 broken contacts that I thought might have been a fuse..? Since I thought maybe I shorted something somehow, I pushed the broken connections together and tested for continuity, then started the car. No change, and that’s where I’m at right.

Why is this happening, what did I do wrong, and where do I go from here? I can not afford to take the car in to a dealer or mechanic.

 

Forgot to mention, went back out later that night to double check the 12 volt battery. Multimeter now reads 11.7 volts.

 

Now that I typed all that and I’m thinking about it, I decided to replace that 6 year old auxiliary battery and see if the check hybrid message goes away.

If you’ve read this far, I have another question.. the electrical connectors inside the fuel pump.. are they protected from the gasoline running through the pump..? Like are they “gas proof” tight? I’m wondering if they could’ve gotten gas in the connectors and shorted the pump maybe..? Also noticed when trying to start the car after messing with the integration module, the tank level showed empty even though it’s pretty full.

 

The battery is like 7 years old, so I’m going to replace it today whether it will charge or not.

Regarding data stream, I’ll have to google. I have a Bluetooth scanner but it’s new for me and I’m not sure how to process the data yet. Hopefully there’s a manual for scanners that’s as good as the OBDII manual.

 

After replacing the 6-7 year old auxiliary battery, everything worked fine . Next move was removing and cleaning the fuel injectors by briefly connecting to the battery and blasting solvent through. Noticed the number one injector was more fouled than the others, possibly explaining the accelerated wear on the corresponding plug..?

Still starts rough sometimes but not nearly as bad as before all this work. This forum pointed me toward TSB 0010-12, regarding an updated intake manifold replacement part to fix the rumbling. Yesterday I took the car in to see about getting it swapped.

If they try to tell me that’s not the problem, I’m going to be out $160 for diagnostics, plus rental car cost .

Also I looked into tech stream and it is over my budget.. good to know about technical info 2 day subscription though for the next time I have an issue.
Thanks!

 

Good to know we can buy individual components instead of an entire pump assembly.

 

Well Wth what I just looking at lol.. I was looking at subscription costs or something.. is there a professional tech stream and a bunch of boot leg knock offs?