Hello all, I am in the process of repairing my 2011 Prius IV and would greatly appreciate any guidance and advice. I have never done any work on any car prior to this. These are the details and current status: The Car A 2011 Prius IV, purchased via private seller (friend) in 2019 at 150k miles. Current miles: 201k Front wheel fender liners and front splash guard had been torn out, seemingly by impact with something on the ground. It was a fleet car for a local business and I think was well maintained but driven rough. Previous owner did high mileage maintenance at dealership around 140k miles. Since the time of purchase, I have done regular oil changes every 4-5k miles. I have not changed the coolant or trans fluid. The car has run well, and I have done a couple of minor repairs in that time unrelated to the engine bay area. There appears to be no mixture of coolant/oil on the dipstick. There seemed to be some of this only around the PCV Valve and it’s hose. The current issues During a cold day about a month ago, SIGNIFICANT shaking upon start up. I did not drive the car for a couple of days, and upon starting it again there seemed to be a misfire (or perhaps other rattling) for only a second. Error Codes at that time: P0401 I removed the entire EGR system and cleaned it. However, due to beginning to strip the screws on the EGR valve, I did not remove the black plastic portion from the valve itself. I did clean inside and outside of the valve and avoided the black part. Cleaned the Intake Manifold and Throttle Body. Replaced PCV valve with an aftermarket PCV, as well as a couple of hoses. I cleaned the MAP Sensor, as it was very gunky. I used a Q-Tip which I did not realize was bad to do. After putting things back together and clearing codes, P0401 became a Historic Code and did not return to being an active code. Additionally, P0108 also showed as a historic code, but wasn’t there as an active code at any point that I noticed. I had driven the car in town for a couple of days since then. I pulled the MAP sensor out again and decided to drip/swirl 99.9% isopropyl alcohol in it. · I now have the codes P0108 and P0403 as active. P0403 was not previously active at any time throughout this entire process. P0401 is listed as Permanent (Archive/Inactive) In Car Scanner Pro: Steady 0% on EGR Valve readings and kPa for the MAP was always at 146 and did not move when doing a 5 minute drive down the street. Also, Dr. Prius showed the HV battery health at 46% for what it is worth. The plan at this point: · Stop driving it until it is fixed. · Install an aftermarket MAP Sensor for the time being, to rule this in/out. · Install an OEM EGR Valve, while keeping the rest of the assembly. · Change the coolant using Toyota SLLC · Run ATS Oil System Cleaner and immediately change the oil/filter · Install a new, OEM water pump · Install front splash guard and fender liners · Install 50% tint in back windows · Install/upgrade stereo to E7022 unit (Have the unit, waiting on replacement Nav DVD. Based on all of this information, I am wondering if anyone has any ideas for the resolving the error codes, as well as ideas on what is happening (I am wondering if: I’ve broken the EGR valve and MAP Sensor myself). And otherwise, I would love any advice that could help extend the car’s life. I had a Gen 2 Prius for about 7 years before this one, which I loved and never quit on me. I love this one too and I am hoping to keep it going as long as possible.
You have done quite a lot of work. It is possible that something is not latched somewhere. Check all the connector connections again. And check the tubes and connectors for proper tightening so that there is no air leakage. P0403 Open or short in EGR valve circuit (1 trip detection logic) Trouble Area: Open or short in EGR circuit EGR valve assembly ECM P0108 The output voltage from the manifold absolute pressure sensor more than 4.5 V for 0.5 seconds. (1 trip detection logic) Trouble Area: Open or short in manifold absolute pressure sensor circuit Manifold absolute pressure sensor ECM If you have been operating a hybrid car for a long time, you should understand that universal applications for diagnosing conventional cars are not suitable for diagnosing a hybrid.
Thanks for the reply, I'll check the connections again when I get back in there. The apps I have used are Torque, Hybrid Assistant, Dr. Prius, and Car Scanner Pro, but primarily Torque throughout this. Is there a best-by-test app for diagnosing and working on Priuses?
I also use Torque, Hybrid Assistant, Dr. Prius. This is a phone and an ELM327 adapter. For more detailed diagnostics Techstream, I think the last version installed on the laptop was 18. There are other devices for diagnostics, but there is probably no universal one. Look at this topic. Gen2 OBD2 app review | Page 2 | PriusChat
Probably head gasket failure. Considering the hopelessly bunged up “before” pics of the EGR, it would not be doing its crucial job, tempering combustion chamber temps, for some time now.
Thank you for reading/replying, I had read some of your links/materials going into this repair, and have hoped for the best that it would not be a HG failure. Could you give me any advice on what to do from this point? Would replacing anything noted (ie. water pump, fluids) make any difference in getting more life out of the car, or would it make no difference at this point? For what it's worth in general, I installed an aftermarket MAP sensor this evening and sprayed the contacts of the MAP and EGR with cleaner, and the error codes and CEL turned off. I drove for awhile, monitoring with Car Scanner Pro; kPa was in normal range, and EGR valve is functioning now.
Borescope inspect the combustion chambers, morning after a previous driving day, preferably with cooling system pressurized. You’re looking for: coolant tears commencing from head gasket seam coolant pooling atop piston exceptionally clean top of piston Not sure if you’ve been there, but if not: getting the spark plugs out is “fun” on this gen, requires removal of wipers, their motor and linkage, and the underlying metal cowl. See video #13 here: Nutz About Bolts Prius Maintenance Videos | PriusChat you’ll need 14 mm or 9/16” spark plug socket. Contrary to video, plugs are 15 ft/lb with clean/dry threads.
Again, thank you for the reply and advice, it is a huge help. I had the wiper assembly/cowl off already, so I will go ahead and take a look with a borescope. I'll post a comment in this post with an update/photos for future googlers looking for information. Thanks again.
The Borescope I purchased isn't very high quality. I am not sure what I am looking at, but a potentially notable things is that the photos taken, in cylinder 3, a couple of the valves seem to be a different color than the rest of the valves across all cylinders. I don't think it is very easy to see this in the photos I posted.
