P0172, P0446, P0300 Try to diagnose.
Thread Starter
New Member
Joined: 09-06-2022
Posts: 27
From: Vancouver BC Canada
P0172, P0446, P0300 Try to diagnose.
In need of help. After much searching and reading here and all over the interwebs, I come to you guys for further help.
I sent the car in to mechanic to have the shocks and water pump changed.
He used a "special tool" to hold the timing chain so nothing would move when removing the water pump.
I picked the car up and in ran like absolute crap. I took the car back and after the mechanic had it for a while, and threw numerous parts at the car, we are still having issues.
I have since brought the car home and have been using my Span-On scanner to try and diagnose the issues.
Error Codes:I am getting P0172, P0446, P0300
P0172 Code: Fuel Trim Too Rich (Bank 1)
P0446 Code: Evaporative Emission Control System Vent Control Circuit Malfunction
P0300 Code: Random or Multiple Cylinder Misfire Detected
What I and the mechanic have changed or "fixed"on the car.
- water pump
- shocks
- fuel pump
- rear evap canaster sensor
- O2 sensors
- MAF sensor
- Both Variable valve timing solonoids (which had a code but code went away after) - reset Fuel Alcohol to 0 (was at 39 and 59) (staying at 0 since)
- reset high and low Fuel Trims
- new throttle body
- oil pressure sensor
- ignition coils
- spark plugs
- ran diagnostics on fuel injectors and scanner shows all okay.
- both new timing chains, guides, sprockets- smoke test - (no leaks other than oil fill tube on valve cover)
- compression test good and equal across all cylinders
Idle still rough when cold.
Fuel trims have improved from the new timing chain and stay closer to 0 but when the engine is cold, it runs rough and spikes SLTF and LTFT every few seconds.
Speeding up engine makes the fuel trims improve towards 0 signaling a vacuum leak but smoke test revealed no leak.
I'm hoping to figure this out as the mechanic decided to load the parts cannon and costed me a lot of money in parts I may have not needed.
(2010 2.2L VVT)
Thanks in advance!
I sent the car in to mechanic to have the shocks and water pump changed.
He used a "special tool" to hold the timing chain so nothing would move when removing the water pump.
I picked the car up and in ran like absolute crap. I took the car back and after the mechanic had it for a while, and threw numerous parts at the car, we are still having issues.
I have since brought the car home and have been using my Span-On scanner to try and diagnose the issues.
Error Codes:I am getting P0172, P0446, P0300
P0172 Code: Fuel Trim Too Rich (Bank 1)
P0446 Code: Evaporative Emission Control System Vent Control Circuit Malfunction
P0300 Code: Random or Multiple Cylinder Misfire Detected
What I and the mechanic have changed or "fixed"on the car.
- water pump
- shocks
- fuel pump
- rear evap canaster sensor
- O2 sensors
- MAF sensor
- Both Variable valve timing solonoids (which had a code but code went away after) - reset Fuel Alcohol to 0 (was at 39 and 59) (staying at 0 since)
- reset high and low Fuel Trims
- new throttle body
- oil pressure sensor
- ignition coils
- spark plugs
- ran diagnostics on fuel injectors and scanner shows all okay.
- both new timing chains, guides, sprockets- smoke test - (no leaks other than oil fill tube on valve cover)
- compression test good and equal across all cylinders
Idle still rough when cold.
Fuel trims have improved from the new timing chain and stay closer to 0 but when the engine is cold, it runs rough and spikes SLTF and LTFT every few seconds.
Speeding up engine makes the fuel trims improve towards 0 signaling a vacuum leak but smoke test revealed no leak.
I'm hoping to figure this out as the mechanic decided to load the parts cannon and costed me a lot of money in parts I may have not needed.
(2010 2.2L VVT)
Thanks in advance!
Last edited by Oxygen454; Sep 7, 2022 at 04:43 PM. Reason: Paragraph jumbled together, hard to read
Administrator
Joined: 10-13-2011
Posts: 40,082
From: Welland,Ont Canada
I suggest a battery lobotomy, simply disconnect the negative cable at the battery in the back beside the spare tire for a few minutes, to reset the computers. Reconnect the terminal and start it up.
Moderator
Joined: 01-23-2009
Posts: 26,532
From: Fredericksburg,VA
Boy, that guy can retire now. Is there a way to report him to authorities?
He really did all of that on the basis of those 3 codes?
First the Span-on scanner has incorrect names for the tests:
P0172 is fuel TRIM system rich. That means that the computer is trimming the fuel system rich because it thinks it is lean.
P0300 is UNIDENTIFIED misfire detected.
What is a
I never heard of that.?
What does a water pump or shocks or oil pressure sensor have to do with anything?
Have you looked at the exhaust flex pipe?
Why not look at the canister vent valve and its wires or fuse, since that is what P0446 means is broken.
Have you looked at the under hood EVAP purge valve? It should be normally closed; blow into it to test.
Have you checked the MAF connector and wires?
Unless you have done some studying don't think a scanner response means what it says. The code descriptions are generic names of OBD2 tests, not what the mean or what they test. If the guy that programmed the scanner wanted P0172 could be "John" that means as much as "Fuel System Too Rich (Bank 1)"
He really did all of that on the basis of those 3 codes?
First the Span-on scanner has incorrect names for the tests:
P0172 is fuel TRIM system rich. That means that the computer is trimming the fuel system rich because it thinks it is lean.
P0300 is UNIDENTIFIED misfire detected.
What is a
rear evap canaster sensor
What does a water pump or shocks or oil pressure sensor have to do with anything?
Have you looked at the exhaust flex pipe?
Why not look at the canister vent valve and its wires or fuse, since that is what P0446 means is broken.
Have you looked at the under hood EVAP purge valve? It should be normally closed; blow into it to test.
Have you checked the MAF connector and wires?
Unless you have done some studying don't think a scanner response means what it says. The code descriptions are generic names of OBD2 tests, not what the mean or what they test. If the guy that programmed the scanner wanted P0172 could be "John" that means as much as "Fuel System Too Rich (Bank 1)"
Thread Starter
New Member
Joined: 09-06-2022
Posts: 27
From: Vancouver BC Canada
Thanks for the replys.
He's a semi retired mechanic working from his house. He's old school mechanics, doesn't understand the new sensors and technology apparently. He did all this work to try and fix what he though he may have damaged while doing the shocks...
The P code definitions I posted were just a quick google and post while writing that novel up here lol. Not what the scanner was showing.
The part I believe is actually called rear vent control solonoid.
(The car went in for shocks to be replaced and the water pump, when getting the car back, it ran like crap, then all this began) Most of the parts was paid by him luckily but not all, while trying to "diagnose" this. Guess he's never heard of testing parts first.
Tried pulling the battery for 1/2 and didn't help.
Tried blowing through the evap purge valve, air was a bit hard to blow through. It pulses like crazy when the car is running. Is that normal?
I will run the scanner again and watch the fuel trims.
The MAF is new and is reporting around 6gm/sec. I will take a look at the wiring.
Anything else I should be looking at?
I wish I knew how to print reports off this scanner but the scanner is way more technical than my knowledge. SnapOn Modi's.
He's a semi retired mechanic working from his house. He's old school mechanics, doesn't understand the new sensors and technology apparently. He did all this work to try and fix what he though he may have damaged while doing the shocks...
The P code definitions I posted were just a quick google and post while writing that novel up here lol. Not what the scanner was showing.
The part I believe is actually called rear vent control solonoid.
(The car went in for shocks to be replaced and the water pump, when getting the car back, it ran like crap, then all this began) Most of the parts was paid by him luckily but not all, while trying to "diagnose" this. Guess he's never heard of testing parts first.
Tried pulling the battery for 1/2 and didn't help.
Tried blowing through the evap purge valve, air was a bit hard to blow through. It pulses like crazy when the car is running. Is that normal?
I will run the scanner again and watch the fuel trims.
The MAF is new and is reporting around 6gm/sec. I will take a look at the wiring.
Anything else I should be looking at?
I wish I knew how to print reports off this scanner but the scanner is way more technical than my knowledge. SnapOn Modi's.
Moderator
Joined: 01-23-2009
Posts: 26,532
From: Fredericksburg,VA
The EVAP FUSE #64 under hood. The flex pipe. No, the purge valve should not cycle like crazy. The MAF plug on the air cleaner tube was probably the original problem.
It is beyond my understanding how changing the shocks and water pump could cause the problems described.
It is beyond my understanding how changing the shocks and water pump could cause the problems described.
Thread Starter
New Member
Joined: 09-06-2022
Posts: 27
From: Vancouver BC Canada
I will have to update the original post. The shocks and water pump was what I wanted the mechanic to change.
Then when I brought the car back when it was running rough, that's when things went sideways.
I could have done the work myself but I figured it would be easier to go to work while someone did the wrenching for me haha.
Oil pressure and fuel pressure were good yet he changed the oil sensor and fuel pump, then the O2 sensors... I don't know what he was thinking.
I'm going check the fuse and probably change the purge valve. Only good thing is I'm running out of sensors to change because the mechanic did the rest of them.
Then when I brought the car back when it was running rough, that's when things went sideways.
I could have done the work myself but I figured it would be easier to go to work while someone did the wrenching for me haha.
Oil pressure and fuel pressure were good yet he changed the oil sensor and fuel pump, then the O2 sensors... I don't know what he was thinking.
I'm going check the fuse and probably change the purge valve. Only good thing is I'm running out of sensors to change because the mechanic did the rest of them.
Moderator
Joined: 01-23-2009
Posts: 26,532
From: Fredericksburg,VA
He was replacing everything mentioned as a possibility instead of testing to find out what was wrong. Thankfully you got it away from him before he got to replacing the computers.
Like I said, most likely cause of the poor idle is he forgot to plug the MAF back in or the plug isn't secure. He probably blew the fuse when he replaced the the vent valve. Fuel trim might be caused by using the wrong brand O2 sensor or a cracked flex pipe.. Smoke tests rarely show anything, I don't know how it got into the crankcase.
Like I said, most likely cause of the poor idle is he forgot to plug the MAF back in or the plug isn't secure. He probably blew the fuse when he replaced the the vent valve. Fuel trim might be caused by using the wrong brand O2 sensor or a cracked flex pipe.. Smoke tests rarely show anything, I don't know how it got into the crankcase.