Hello all, My first post here & I apologize its a bit long. My Gen 2 prius (158K miles) has several codes and poor fuel economy (33 highway). Hope to get insights from y'all on the diagnosis and possible next steps. On a recent long road trip it was raining for the most part. The following codes showed up during the return journey and have stayed solid since then. Codes: P0AFA, P0AC0, P0016, P3000-123, ABS: C1310, C1241, C1259, C1378 I used techstream to try diagnosing issues. Here is what I did so far: - Old 12V Battery swapped with a brand new compatible battery (DieHard Platinum AGM) after the road trip -Sealed the hairline cracks near the trunk door trim and there is no more moisture inside the car trunk. The 12V battery well and other places are dry. - Cleaned corrosion off the copper terminals and nuts (Salt+Vinegar and baking soda) and reinstalled them. - There was little corrosion on 2 terminals of the orange connector to the hybrid battery ECU. Cleaned all terminals of the plug and the battery ECU connector. Cleaned visible corrosion on the inside of the battery ECU terminals. - Cleaned and checked all wires running from hybrid battery to ECU using a multimeter and saw no issues with connectivity. - Checked all car fuses and they are okay. I know of the orange disconnect for the HV and I make sure to 'push it down'. A possibly relavant problem: After a recent car wash, the 12V battery discharged to 11.6V (from car's dashboard display). Person at Advanced Auto checked the voltage after disconnecting battery from car and it was >12.1V. Voltage went up to 13.8V after ignition on. Since the wash the pickup of the car from a stop has noticably become really slow. Techstream shows that HV battery modules 2 and 3 often fluctuate between 16 and -15.84 V. All other modules stay around 16.2V. I haven't run a load test on individual modules (don't have the right equipment) I cleared trouble codes using TechStream but they still reappeared. I would like pointers for diagnosing these issues and possible next steps - The 12V battery issue indicates a short somewhere that got worse with the car wash. Where are possible points check that? - I am planning to disassemble the hybrid battery and change the 2 cells with fluctuating voltages. What else can I check while I am in there? Could there be another source of problem other than the cells? - Do you think it is a problem with the hybrid ECU? - Suggestions about the P0016 error? Thanks,
Welcome to PriusChat!! Put together a crazy long write up for you, then PChat lost it on a refresh. So I will try again, in smaller pieces/posts this time. When replacing/disconnecting the 12v, always clean the MAF as well, unless you've recently cleaned it. If it was raining, you can check for water in the spark plug wells. First use a multimeter between the negative battery post and ground, confirm the amperage draw when off, then post results here. Those modules could be fine, and the voltage variance you are measuring could be from burnt pins or corrosion in the HV battery ECU/connector and or in the No. 2 wire frame, which are the thin gauge wires used for voltage sensing (pic below), costs under $60 new, part # 82165-47040 Might check the white connector near the HV battery fan, and both sides can get pretty bad. Unlikely, but anything is possible. With that kind of mileage, it is likely from a miss or a vibration. You may need new spark plugs at 158k, or just check for and clean up the 'carbon tracking' on the plugs and coils (COPS). Here is the workup for DTC P0016 : 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/05/2054m/cip0016.pdf[/QUOTE]
Techstream shows that HV battery modules 2 and 3 often fluctuate between 16 and -15.84 V. All other modules stay around 16.2V. That sentence alone says a lot. Batteries do not, and cannot, fluctuate through that range. Measurements and Indications can, due to the way they are measured/calculated. As mentioned above, you have a wire harness, ecu or ecu pin problem. Most commonly, it's the wire harness, especially after it's been disassembled/reassembled. Between loose connections, bits of corrosion, cracks in the crimp area, etc, it's much easier to just order a new wire frame #2 as mentioned above. Always start by fixing the most obvious problem first. Sometimes all the others just go away afterwards.
Hello again.. I really appreciate all your inputs. I tried few different things over the past 2 weeks and need few more pointers. I changed the serpentine belt, VVT valve and cleaned its filter. I am still tracking as I drive more but over 3-4 short trips in the city there was no "current" P0016 code yet. Things are still not resolved with the hybrid battery. I changed the battery harness assembly that goes with the black negative cable. This was done with expectation to address the negative to positive swing in few module voltages. I didn't see this issue reoccur. I also changed the battery ECU. Had Advance Auto put the 12V battery on their "fast charger". Their test equipment showed 12.35 V (don't know how accurate it is) and 425 CCA for a battery rated for 370 CCA (cold) & 510 CCA. Since just before I opened HV battery to change the wireharness and ECU, I am having a peculiar issue. After 5-10 mins of driving the HV battery fan comes on and stays at 6 all the time. The "Active Test" in Techstream shows that the 3 temperature sensors show 60-75 F (intake air temperature in 70s or less) but the fan still stays on 6 all the time. When this happens the engine does not switch off when, car stops at a red light. Eventually after a little more driving the battery seems to disconnect (from the MFD display graphic) and the car seems to run only the on gas engine. Interestingly, after clearing all DTC codes everything seems to become "normal" for 2-3 short trips and then the fan comes back on and stays on most of the time. So far I have seen P3000-123, P3016 (weak module 1), C1259 & C1310 codes. I have cleared codes twice and P3000 did not show up after short trips yet. I haven't driven too long as the fan running on high is concerning me a bit. I understand the fan is typically triggered when the battery tempr sensors detect higher values. Is there somethings obvious I may have missed? I have verified that all plugs are connected properly. Next things on my list are to figure out a way to load test individual modules but before putting in time and buying a charger/tester I want to make sure if it will be worth doing that. How do I figure out if it is just a couple bad modules or majority of the modules that need replacement. Please suggest possible next steps. Thank you. I just love this forum!
The problem is the P3016. Block 6 of the battery is weak. That code is the one putting you into limp mode and putting the fan at full speed.
one: sell the car or trade it in two: replace the hv battery with a new Toyota or aftermarket (2K1Toaster on this forum) three: get a complete used pack from a junkyard and pray four: replace a few modules and pray five: get a "rebuilt" battery (or rebuild service) and pray six: get RC hobby chargers to cycle your modules (and replace as needed) seven: replace failed modules and use the Prolong battery grid charger and discharger Other than seeing an obvious voltage differential (typically 1V+ due to a shorted cell) on a failed module, you can't evaluate modules with out performing charge/discharge cycles to check capacity, load testing, and watching voltage over time for self discharge problems. Really, your budget and expectations for the car will determine what you should do. If you want maximum (10 year +) reliability- get a new battery. Anything less is just buying time, you still would have used modules with lots if years and miles on them. Might be good for a month, a year, two years, who knows?
