DIY Head Gasket complete! Now error codes...

Thank you for everyone who contributes to solutions on this forum. I’m looking at you @Mendel. Don’t be afraid to add a QR code for grateful readers to send you a gratuity over paypal or something.


Writing this a second time after my first copy disappeared when page refreshed.


In January my 2012 Prius II with 360,XXX miles began to sputter at low RPMs. My coolant was disappearing. My head gasket was done.


I hired a mobile hybrid mechanic who quoted me $1200 to do the gasket but he convinced me to do basic services first before a head gasket job. He cleaned MAF, EGR, replaced spark plugs, and billed me the original price for the gasket. I drove the car briefly, considered it fixed, and paid the man. After driving it more than ten minutes the next day it became clear that the problem remained; and my mechanic did not want to return to do the gasket job (or couldn’t). Whatever.


I rolled up my sleeves, watched the gasket masters video ad nauseum, bought the parts and tools, and went to work.


I replaced the head gasket, 12V battery, PCV, and water pump. I tried firing up the car several iterations. Each time it came to life for 8 seconds and died with a check hybrid system warning. Reading other threads allowed me to discover how many connections I did not plug in (The black coolant thermostat on the top of the engine on the right, and the black plug in the back of the air intake behind the filter).


I fired up the car today and it lasted nearly 30 seconds. No nasty metal sounds… smooth as butter really… So i'm getting more confident that I did the timing chain correctly and that the Cams were seated in the correct position. During that 30 second interval I also checked the exhaust coming from the tailpipe which was warm and not rich (soooo ive got fuel and sparks… right?).


Well now the HV battery is in protection mode.


My musings for your considerations:

1. Is a low volts in HV the cause of my prius to not stay alive? I hoped that on that last ignition that the ICE would stay alive and begin to charge the HV battery.
   
   
2. Now i have to get volts up on my HV. Can i buy one of these Prolong/MAXX Watts conditioners to push grid power into cells? Any other solutions to charge the HV battery?
   
   
3. On one attempt, while the engine was running, I pushed on the accelerator to try "italian tuning". Maybe increasing revs would work out kinks like air in the fuel line or something. Little/No response from engine. Is this a symptom? I forgot if the engine can be revved in park.
4. Lets say I have another culprit for low ICE power and my symptoms What are your thoughts considering the evidence? I have not taken out air intake and throttle body yet to see if there are any throttle body culprits yet.

Error codes are

P0102: Mass air flow circuit low

P0113:Intake Air Temperature Circuit High Input

P0118: Engine Coolant Temperature Sensor 1 Circuit High

P3190: Poor Engine Power

P0A0F: Hybrid drive system - engine failed to start (this code is now gone)

Some of these may be resolved after plugging in the correct plugs but they showed after I took corrective action and cleared the computer.

This DIY project has been a great experience to learn about the miracle of ICE and I've gained an appreciation for (honest) everyday mechanics. I have some grit and money left in me to taste sweet victory if someone here can get me across the finish line. I'll treat you to a beer here in Atlanta.

 

I completely agree. I justified the work by just a sheer curiosity about dismantling the engine far enough to rule out hamsters behind the curtain making the thing run. I ran the VIN through Toyota. The first owner owned the car for a couple years and put on 30k miles. The second owner put on the next 200XXX. No records online. I used insurance money (6k) to buy this model when my 2010 200k mile prius was totaled. It is NOT a buyers market out there for used cars. To answer your question, i suspect "No" to your maintenance questions. I dont have a trained eye for engine internals but nothing looked obscene. I did not have the surfaces machined. The cylinder wall seemed smooth (i think too smooth is bad right? no ability for oil to cling and lubricate?).

Code P3000 for battery. I will update my original post.

Thank you for your interest! Keeping my fingers crossed that PCV or other simple connecter/hose is the culprit.

 

I agree on all fronts. I owned the car last year and put 100,xxx miles on it. owned a 2010 before for 7 years and loved it. now i want to embrace the maintenance instead of fearing it.

See if you think the picture is of OEM head gasket. Not sure here.

 

Awesome advice! Whats the mood on the forums regarding Prolong Vs MaxxVolts. Will they both get the job done? Im not a huge fan of electricity but I can do basic stuff. Not so interested in rigging a contraption... its just not my forte. Im ok to pay $350 or so for a MaxxVolts then sell it for less back on ebay.

Anyone reading have a charger in Atlanta area??

Oh yeah for what its worth there is a GreenTec here in atlanta with an entry level refurb batter for less than 1400$... had me thinkin...

 

There is a seeming trend of South-of-the=border friends doing awesome work in the refurb battery market as far as i can tell on youtube.

 

Thank you for the heads up! I will shop around. Right now my course of action is to grid charge my existing battery and look for those pesky connectors and hoses which may be the issue. Today I removed the air intake to check occ connections and MAF sensor seated properly. They looked good. What are your thoughts on butterfly valve? Mine looked squeaky clean.

 

I inspected MAF sensor and connectors. Everything looked good. I don’t know what an old sensor looks like but dare I say this one looked so good it could may as well be new?

 

Thank you for the idea. I planned out your suggestion but I chickened out. I need to get more confident with electricity. MaxxVolts charger arrives monday. Hoping a charged HV will solve the problem

 

I did more testing today. With “Car Scanner” I was able to verify that the car is pulling live MAD and IAT and coolant temperature data. I suspect these codes may be permanent until operating conditions (ie highway driving) clear them.
Now, I’m left with a smoothly operating, low power motor. Often the computer shuts the entire down before 10 seconds. However I recently had it run 30+ seconds. The ICE has a meager idle of 900 RPM. If I shift the car into gear, the car instantly shuts down. On a stronger iteration, it will rise to 1200 RPM idle. On these occasions I have been able to reverse. I don’t dare drive the car out of my property lest I become stranded.

Bottomline. I have fuel, air, and spark to sustain a weak engine. Yes I have codes, but the live data from the coded sensors makes me confident that they are not culprits.

Someone please entertain the idea that my timing chain is not perfect. Yes, I paid extra attention to timing chain while doing the head gasket job. However if it is off by one link somewhere would it still result in a smooth, quiet, albeit weak, engine operation? There is no obscene noises (and knocking is gone… yay head gasket?).
Standing by for some confident input before I start all over again and disassemble the engine to check my work.

PS I installed Maxx Volts harness to keep HV battery from being depleted from starting engine during trouble shooting.

I have a lot more fight in me to avoid the car dealer lot. Learned to love my Schwinn again

 

New code: P0016 - Crankshaft position/camshaft position, bank 1 sensor A - correlation
Crankshaft Position / Camshaft Position Bank 1 Sensor A Correlation
Status: Pending

I’m starting to zero in on an idea of where the issue is but I’d like to hear a few others suggest what could be causing engine Prius to shut down. Reminder that when I first start the car, it can run in excess of a minute… hell, I moved it around the driveway. The engine eventually shuts off. Subsequent restarts result in engine living less and less until it doesn’t live past MG1 spin up.

similar cases indicate oil being overfilled. I checked the stick (just replaced oil) and it’s dead center with two dots. Add’l when I fill the engine with oil from empty, I basically use 85% of a gallon jug. I’m pretty sure overfilled oil is not the issue.



Full Report:

Car Scanner ELM OBD2
Version: 1.98.6/1.98.6/iOS
DTC report
Connection profile: Toyota Prius Gen.3 2010-Date: 5/5/2023 3:54:34 PM
============================
OBD-IIOBD-II
DTCs: 6
----------------------------
P3190 [0x3190]
Poor Engine Performance; Poor Engine Power (Pri)
Status: Confirmed
----------------------------
P0016 [0x0016]
Crankshaft position/camshaft position, bank 1 sensor A - correlation
Crankshaft Position / Camshaft Position Bank 1 Sensor A Correlation
Status: Pending
----------------------------
P0102 [0x0102] Archive (inactive)
Mass air flow (MAF) sensor/volume air flow (VAF) sensor - low input
Mass or Volume Air Flow Meter Circuit Low Input
Status: Permanent
----------------------------
P0113 [0x0113] Archive (inactive)
Intake air temperature (IAT) sensor - high input
Intake Air Temperature Sensor Circuit High Input
Status: Permanent
----------------------------
P0118 [0x0118] Archive (inactive)
Engine coolant temperature (ECT) sensor - high input
Engine Coolant Temperature Sensor Circuit High Input
Status: Permanent
----------------------------
P0A0F [0x0A0F]
Hybrid drive system - engine failed to start
Status: Confirmed
============================
Engine control unit #1Engine control unit #1
DTCs: 1
----------------------------
P3190 [0x3190]
Poor Engine Performance; Poor Engine Power (Pri)
Status: Confirmed
============================
ABS control unit #2ABS control unit #2
DTCs: 2
----------------------------
C1259 [0x5259]
Status: Confirmed
----------------------------
C1310 [0x5310]
Status: Confirmed
============================
Hybrid engine systemHybrid engine system
DTCs: 1
----------------------------
P0A0F [0x0A0F]
Hybrid drive system - engine failed to start
Status: Confirmed
============================
Motor generator
No DTC found.
============================
Gear selector switch
No DTC found.
============================
Telematics
No DTC found.
============================
Dashboard/Instrument cluster #1
No DTC found.
============================
Climate/Heater
No DTC found.
============================
PM1 gateway
No DTC found.
============================
Entry & start / Smart key
No DTC found.
============================
Power source control
No DTC found.
============================
Electric windows main switch/control
No DTC found

 

New code: P0016 - Crankshaft position/camshaft position, bank 1 sensor A - correlation
Crankshaft Position / Camshaft Position Bank 1 Sensor A Correlation
Status: Pending

I’m starting to zero in on an idea of where the issue is but I’d like to hear a few others suggest what could be causing engine Prius to shut down. Reminder that when I first start the car, it can run in excess of a minute… hell, I moved it around the driveway. The engine eventually shuts off. Subsequent restarts result in engine living less and less until it doesn’t live past MG1 spin up.

similar cases indicate oil being overfilled. I checked the stick (just replaced oil) and it’s dead center with two dots. Add’l when I fill the engine with oil from empty, I basically use 85% of a gallon jug. I’m pretty sure overfilled oil is not the issue.