All the EVAP codes!

[HelloThere]

Well hello there. I'm terrible at writing so sorry about that in advance. I have a 2014 iQ that I just bought not too long ago that keeps popping up different evap codes. First it was P0441 - incorrect purge flow. I cleared it with my basic code reader and drove around some more until the check engine light came on again (as well as the traction control disabled light if that's relevant) this time with P0456 - very small evap leak. The car had an aftermarket gas cap so I ordered an OEM one but the CEL went out on its own while driving before I changed the cap. The P0456 was still listed as a stored code and my reader said the vehicle evap system hadn't passed its tests. I got the OEM replacement cap, replaced it, and drove around a bunch but the P0456 code came back.

I figure I must have a leak somewhere and asked the mechanic near me to have a look at it. They can't find any leaks and say that the OEM gas cap feels like it doesn't tighten very well and that could be the issue. They cleared the code for me and said to try another cap. I bought the cheapest gas cap I could find on Amazon and drove it for a while and all seemed well. I checked on my code reader and the vehicle says evap system finished it's tests. Victory I thought! The very next day I start the car and the CEL comes on immediately. After finishing my drive I plug in my code reader and I have so many codes now.

P043E - Evaporative Emission System Leak Detection Reference Orifice Low Flow

P043F - Evaporative Emission System Leak Detection Reference Orifice High Flow

P2401 - Evaporative Emission System Leak Detection Pump Control Circuit Low

P2402 - Evaporative Emission System Leak Detection Pump Control Circuit High

P2419 - Evaporative Emission System Switching Valve Control Circuit Low

I have a bad feeling there might be something up with the ECM with how varied and opposite the codes are but wanted to see if anyone had any ideas on how I could narrow down what might be the cause of all these codes. Thanks in advance!  

[flash22]

1.0 or 1.3

none of the last 5 codes make any sense

what scan tool are you using, replace the fuel cap with the correct one or put the old one back and clear the codes

[HelloThere]

2 hours ago, flash22 said:

1.0 or 1.3

none of the last 5 codes make any sense

what scan tool are you using, replace the fuel cap with the correct one or put the old one back and clear the codes

1.3

I didn't think they made any sense at first either but it seems like there are quite a few posts on various Toyota forums for this grouping of codes. I honestly didn't expect that so I never searched all the codes at once. Vapor canister seems like a common mention for a potential cause. It seems fairly easy to remove the canister on an iQ so I may have a look at that.

I have an OBDLink LX code scanner I believe. One of those ones that works with an app on your phone. I do plan on putting the OEM gas cap back on but I still had code issues with that one as well so I'm thinking something else is up with the evap system.

Thank you for the reply!

[flash22]

The IQ does not use a leak detection pump, so can't use Leak Detection Reference Orifice

it may be the software you are using, is it just using generic obd2 or manufacture specific information

what is your location, is it a Toyota IQ or a Scion IQ

 

was the evap system smoke tested ?

[FROSTYBALLS]

From the IP Address it is likely the OP is in the US .........

[HelloThere]

11 minutes ago, flash22 said:

The IQ does not use a leak detection pump, so can't use Leak Detection Reference Orifice

it may be the software you are using, is it just using generic obd2 or manufacture specific information

what is your location, is it a Toyota IQ or a Scion IQ

 

was the evap system smoke tested ?

That's interesting.

I have to assume it would be generic as it didn't know what P043E or P043F codes were and labeled them as "Manufacturer Defined"

I'm in the states so it's technically a Scion.

5 minutes ago, FROSTYBALLS said:

From the IP Address it is likely the OP is in the US .........

Correct! The ........ is ominous. 

[flash22]

that makes sense the US market cars are setup differently from the JDM/EU cars, I will have to look into the evap setup on the NA cars

 

[flash22]

Yes, it is a very different system than the EU/JDM cars it uses a vacuum regulating valve and purge valve on the charcoal canister - you should be able to hear the valves click running an active test basically a purge and seal test

where are you in the US, any rodent damage or smell of pee ? any smell of fuel

[HelloThere]

On 8/31/2024 at 10:38 AM, flash22 said:

Yes, it is a very different system than the EU/JDM cars it uses a vacuum regulating valve and purge valve on the charcoal canister - you should be able to hear the valves click running an active test basically a purge and seal test

where are you in the US, any rodent damage or smell of pee ? any smell of fuel

I forget to answer your previous question about the smoke test but the mechanic I took it to did a smoke test and couldn't find any leaks. I haven't noticed any evidence of rodent damage, pee smell, or any fuel smell.

I'm pretty sure the device I have just reads codes and can't do tests like that. I was planning on testing the valves by removing them and actuating them with a 12v power source off of the car. Will probably pull the canister and see if anything seems off it too. Hoping to get into that next weekend and see if I can find anything.

Thank you for the replies!

 

[HelloThere]

I ended up having time yesterday to have a look at things. Tested the solenoid in the engine bay by connecting the leads to the Battery and that works as it should. The one tube is looking rough but I don't think it's leaking. 

Took out the vapor canister and I can't tell if anything is wrong with it. Wasn't sure how to text the pump sub assembly on the canister and also couldn't remove it from the canister. Was afraid to pull on it too much for fear of breaking something. No blockages in the canister or any lines that I can find. 

I put everything back together with dielectric grease on the connectors and some on the hose lines to help things seal maybe (didn't have any other grease that would work and I don't see how it would hurt.)

Also attached a screenshot of some of my details my scanner had. Purge flow errors but still not sure of the cause. I put the OEM fuel cap back on and reset the codes. One thing of note is that previously when I would reset the codes and the vehicle was running on baseline settings it would idle really low and stall out at first. After it ran for a bit and could adjust itself the idle would come back up and seem good. However this time after the code reset it idled just fine without issue. 

I'll be driving the car around over the next couple days and we'll have to wait and see what happens. 

[flash22]

the canister and sensor are 1 piece oem is expensive and Dorman, Cardone and BWD are 95% junk

if you are in the Rust Belt or where they salt the roads it's likely to be the canister

[HelloThere]

3 hours ago, flash22 said:

the canister and sensor are 1 piece oem is expensive and Dorman, Cardone and BWD are 95% junk

if you are in the Rust Belt or where they salt the roads it's likely to be the canister

Ah that's why you asked where I was previously. I miss things and then realize after. I'm in Pennsylvania, very much in the rust belt.

From my research it seems like canister issues are somewhat common in Toyotas so it makes sense. Part number should be 77740-74010 and looks like it's just under $300. If the codes come back, which they probably will, I'll order a replacement canister and try that.

[flash22]

Evap issues seem very common in the States but more so in the Rust Belt, i have been following SMA and Watch Wes Work on YouTube for many a year, i also have relatives in New England and Ontario

[HelloThere]

Replaced the canister over the weekend and drove about 50 miles. From a cold start this morning CEL is on again with P0456. Is that normal for the code to appear at start up and not while driving? I'm definitely getting the vibe that the previous owner had issues with this and sold it for that reason. They mentioned it had a code but it was fixed by replacing the gas cap. Such an annoying issue to find! I suppose I might pull the fuel spout and give everything a once over. Idk

[HelloThere]

Did some poking in the engine bay while it was running and the purge solenoid is clicking rapidly. I don't suppose it's supposed to do that? 

I'm thinking that might have something to do with the low idle. Whenever I come to a stop the ideal gets down to nearly 500rpm and it feels like it's stumbling. 

I bought a cheap solenoid off Aliexpress just in case and I'm going to throw that one in and see what happens. 

[flash22]

it shouldn't be clicking, disconnect the Battery for 15-20 mins then take the car for a 20-30 drive  keep it below 3k rpm till warm let the idle relearn