My car threw a CEL this morning, but absolutely no difference in drive-ability. It was about 27 degrees F out, and I have the winter covers from IDParts installed. My car is also Stage II with the delete. After doing some searching on here I can't find anything definitive pointing to what it could be. Anyone have any ideas? On my simple OBDII reader it read as "Fuel Air Metering", but from what I have read on here it has something to do with the charge air cooler and the flow. Any guidance is greatly appreciated guys!
P026A code this morning
- Thread starter YukonLT
- Start date
yatzee
Top Post Dawg
I've read all about that, and my car has that kit already. But, with the deletes I haven't ever heard of anyone having that issue.
da.hs
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Do you by any chance have the air intake piece removed so as to get air from the "warm" engine bay area rather than straight from the front grille? Dealers do that sometimes on VW instructions as a way of reducing IC icing. In conjunction with the winter front it can cause the issue you describe - due reduced air pressure in the engine bay (happened to me in second winter, before revised intercooler "cold weather kit").
Or are the winter front peices blocking the cold air intake a bit?
Or are the winter front peices blocking the cold air intake a bit?
VeeDubTDI
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P026A = charge air cooler efficiency below threshold.
This is likely due to your winter front blocking air flow over the intercooler. The ECU isn't satisfied with the temperature drop and is throwing a code for it.
This is likely due to your winter front blocking air flow over the intercooler. The ECU isn't satisfied with the temperature drop and is throwing a code for it.
TDI_Coast2Coast
Veteran Member
What he said....
Good news- you're not going to ice up your IC with that code.
Bad news- you're closer to detonation. You don't want to drop that efficiency too far.
Probably too cold to be an issue, but the code is telling you your IC is relatively hot.
And I can tell you why you are getting that code I think...
Normally that cover wouldn't throw a code. But you already have a cover on your intercooler. Kind of. It's called your TSB IC. Or cold weather intercooler...Whatever you want to call it.
That intercooler TSB, in short, reduces the efficiency of your IC below a set ambient temperature. I don't know the exact temperature, but I guarantee your IC is running in bypass at 27F, meaning it is less efficient already. That's what your TSB does. It reduces the surface area of the IC coil via a bypass controlled by a t-stat.
So now you put another blanket on it...So your IC efficiency dropped even further.
If you had the stock IC, you would be less likely to get the code. And you would have more power.
TDI_Coast2Coast
Veteran Member
I think that code pretty much says if you have the TSB IC, you probably shouldn't block off. Probably not going to damage anything, but in actuality, you may be negating any gains.
See if I can explain a little better.
With stock IC, if you block off, you save some heat from the radiator(and the IC), so the engine can warm up faster AND stay as close to the state where the coolant t-stat wants to open as possible, but not open. 190F say. If your t-stat does not get to that state, you need to cover more. Once the t-stat opens, you covered too much and are negating any gains, the more you cover past this point, the more you negate. In a perfect world, you would have variable veins. that would sense when the t-stat opened and would block off the radiator...a Cold weather grille kit. Hmmm maybe a new product?
Let me explain the problem with the TSB IC that I just realized.
As you found out, you can't run a winter cover without a code, which is telling you that you aren't cooling your compressed intake air very well basically. This is just bad for your turbo. Not as bad when it's cold, but compared to an IC that is working more efficiently, it is definitely adding stress to it. The colder it is, the less stress, but IMO, any added stress will shorten it's life. It's life. Stress kills.
Here is where I thought at first the TSB would act like a winter grille. It kind of does. BUT the TSB has a bypass that just goes around the internals of the IC, so that IC on the outside is not blocked, therefore the radiator will flow freely and cool the same. IC will be hotter, but since it's still colder than the radiator, that is not going to help you radiator keep warm. It is going to add HOTTER intake air. That in itself is going to help warm you up, but not as well as blocking off.
Here is the problem. You're IC is already blocked off INTERNALLY. Now if you block off, you reduce airflow over the IC, which already is bypassed internally. So I can actually see that IC getting pretty hot. You will warm up faster, but you are generating such high IAT's, that you are actually probably losing power/economy, plus cooking your turbo...call it slow cooking.
I'm pretty sure if you have the TSB, a winter cover will HURT your mileage once the car is warmed up initially. Will help it warm up super fast(high IAT's). But the second you reach temp and the coolant stat opens, you are risking possible(highly unlikely) detonation if those IAT's get high enough. Which gets me thinking...
Ahh, you may have figure out, by accident, why people detonate their motors...What happens if the bypass sticks open on the TSB IC, past the set temp? Or the the TSB IC bypass t-stat doesn't read correctly?
See if I can explain a little better.
With stock IC, if you block off, you save some heat from the radiator(and the IC), so the engine can warm up faster AND stay as close to the state where the coolant t-stat wants to open as possible, but not open. 190F say. If your t-stat does not get to that state, you need to cover more. Once the t-stat opens, you covered too much and are negating any gains, the more you cover past this point, the more you negate. In a perfect world, you would have variable veins. that would sense when the t-stat opened and would block off the radiator...a Cold weather grille kit. Hmmm maybe a new product?
Let me explain the problem with the TSB IC that I just realized.
As you found out, you can't run a winter cover without a code, which is telling you that you aren't cooling your compressed intake air very well basically. This is just bad for your turbo. Not as bad when it's cold, but compared to an IC that is working more efficiently, it is definitely adding stress to it. The colder it is, the less stress, but IMO, any added stress will shorten it's life. It's life. Stress kills.
Here is where I thought at first the TSB would act like a winter grille. It kind of does. BUT the TSB has a bypass that just goes around the internals of the IC, so that IC on the outside is not blocked, therefore the radiator will flow freely and cool the same. IC will be hotter, but since it's still colder than the radiator, that is not going to help you radiator keep warm. It is going to add HOTTER intake air. That in itself is going to help warm you up, but not as well as blocking off.
Here is the problem. You're IC is already blocked off INTERNALLY. Now if you block off, you reduce airflow over the IC, which already is bypassed internally. So I can actually see that IC getting pretty hot. You will warm up faster, but you are generating such high IAT's, that you are actually probably losing power/economy, plus cooking your turbo...call it slow cooking.
I'm pretty sure if you have the TSB, a winter cover will HURT your mileage once the car is warmed up initially. Will help it warm up super fast(high IAT's). But the second you reach temp and the coolant stat opens, you are risking possible(highly unlikely) detonation if those IAT's get high enough. Which gets me thinking...
Ahh, you may have figure out, by accident, why people detonate their motors...What happens if the bypass sticks open on the TSB IC, past the set temp? Or the the TSB IC bypass t-stat doesn't read correctly?
Hmmm, I wonder how hard it would be to remove the TSB IC kit. Since my EGR is deleted out, there is no use for it now it seems. I wonder if Malone does anything different with the tune if the car has the TSB IC kit? Can they even tell is they are just shipped the ECU? Many questions...
TDI_Coast2Coast
Veteran Member
If you have had an IC event, and your intake manifold is still plugged in, you still kind of "need" it. EGR is only part of the issue. The most important part is that you assure you have no intake restrictions. It's the intake restriction that is the main cause for the IC "icing", IMO. No intake restriction, no need for TSB.
You may be able to eliminate the bypass, but I'm not sure what the ECU would think when the IAT's numbers don't jive. I assume the t-stat function for the TSB IC is added to the ECU via software update. So if you were to bypass(block off) the bypass somehow(allow flow through entire IC) and a tuner could tune out the t-stat(basically undo software from TSB), I would think it would be eliminated. And car would act as if it had stock IC. I could be missing something, but that should work.
As long as the TSB IC(when bypass is closed) has the same efficiency as the stock IC, you should be fine. And below set temp, better.
You may be able to eliminate the bypass, but I'm not sure what the ECU would think when the IAT's numbers don't jive. I assume the t-stat function for the TSB IC is added to the ECU via software update. So if you were to bypass(block off) the bypass somehow(allow flow through entire IC) and a tuner could tune out the t-stat(basically undo software from TSB), I would think it would be eliminated. And car would act as if it had stock IC. I could be missing something, but that should work.
As long as the TSB IC(when bypass is closed) has the same efficiency as the stock IC, you should be fine. And below set temp, better.
VeeDubTDI
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Coast2Coast, the IC kit is a thermostatically controlled flap that bypasses 80% (approximately) of the intercooler when the ambient temperature is below 40 degrees (approximately). This all mechanical - there is no software or sensors controlling its operation.
You're saying that the grill covers are making it doubly hot, which isn't really accurate, because with the grill blocked, the kit should not be in bypass mode.
As for high intake air temps, they will not cause "detonation." These aren't gasoline engines. The engine will not be harmed with these high intake air temperatures, it will just be less powerful.
I would recommend opening a portion of the winter front for the bottom grill. Open just enough to pass enough air over the intercooler to prevent the code from triggering. This will allow you to retain the fast warm-up characteristics as well as keep your fuel economy up as much as possible.
You're saying that the grill covers are making it doubly hot, which isn't really accurate, because with the grill blocked, the kit should not be in bypass mode.
As for high intake air temps, they will not cause "detonation." These aren't gasoline engines. The engine will not be harmed with these high intake air temperatures, it will just be less powerful.
I would recommend opening a portion of the winter front for the bottom grill. Open just enough to pass enough air over the intercooler to prevent the code from triggering. This will allow you to retain the fast warm-up characteristics as well as keep your fuel economy up as much as possible.
TDI_Coast2Coast
Veteran Member
Sorry, I should have worded it better. I'm on the phone/taptalk...hard to type lol. I didn't mean to give percentage of heat gain from the grille to be blocked. I just meant that if you block your grille, you are in essence blocking some airflow(external) away from the IC radiator. If you do that, you Decrease the efficiency of the IC. So the IAT's go up. That I don't think we can argue. Forget the bypass, if you have stock IC.
So we agree stock IC with blocked grille will be just a wee bit hotter. Not much, never gonna notice. But higher IAT's offer less power at same boost. Can we agree on that? Now how much, just higher or lower.
Now add the TSB. It isn't bypassing the outside, if I understand correctly. It is just bypassing the coil(internally...important). So the size of your IC coil is smaller and you said it bypasses 80%??? If so that's crazy if it that thing ever sticks open when it's 100degF you are at full boost and your intake has malfunctioned.
100F air pressurized to 25psi....That has to get pretty hot right. I need to get my charts one of these days. Anyway, my point is. At 25psi, it's going to be HOT! If that bypass stuck, 80% of IC is not helping get rid of it. If your intake manifold is failed (which is why the IC kit is in there to begin with...just pretend Intake flaps are stuck shut.), then you have NO airflow. No air = no air out. I hope you are on the train already, cause this heat train just went down a hill with no brakes.
No air out is important. x volume of intake=x volume of exhaust. Can we agree? That is a valid equation? We have the variable of fuel, but just to make it easier in discussion, let's say coasting down a hill in gear...so fuel is removed from equation for now.
If we agree that equation is correct, let's play with it.
100cfm in = 100cfm out. Check mark, smiley face
50cfm in = 50cfm out. Check mark, smiley face
Ok, now let's complicate it just a bit.
Let's give some value of heat to the cfm, tells us useful info for volume, we don't know if it's 100F or 1000000000F.
Let's just say 1:1 cfm to joules. Keep everything constant in the environment.
So 50 cfm has 50 joules, 100 has 100, etc. I'm just trying to show the heat flow, heat in = heat out minus losses.
So if we flow more air we can carry more heat. Bigger exhaust, it gets out faster. But we have a problem? If what I said was correct, then my exhaust should be 100 joules. Let's just call it 100F, the intake air temp. It's definitely way hotter. Oh that's right the fuel!
We took that intake air, boosted it at 100F to 25psi. We took 80% away from IC if bypass sticks. So what we can't remove stays on the heat train.
So god only knows how hot that intake air is. Now add fuel, with very little air because of a bad intake manifold. You have a rich mix, afterburn, high egts. Bad stuff yo! Unless you went to a tuner and had something taken out. Once that is gone, you can get rid of all that heat, with it, it's got nowhere to go (of course some loss but mostly inside exhaust piping) for a while...Low pressure egr stuck open, with a malfunctioning egr cooler....Rut row. That's some hot stuff going straight into an IC that we already agreed is much less efficient with bypass open. Exhaust flap stuck closed....it's like driving over the GW bridge trying to get out. If everything goes right, it's ok, but too many cars(heat), especially when you keep adding them, can't go anywhere if you keep closing lanes and exits. You get a pile up of heat. Watch a rush hour traffic jam....It builds and go backwards. Always more heat towards the end of the restriction. But if you don't clear the traffic ahead, and keep adding cars, eventually you get gridlock. No movement of HEAT.
So let's think about detonation. I only brought it up, because I swore in the IC thread I read someone say they detonated, but I, like you, said no way....But the code you diagnosed got me thinking. And you saying 80% only strengthened my suspicion.
Covering up a car with TSB can REDUCE efficiency enough to trigger a CEL. What happens when it's hot? Now this is where I would think ECU would step in at some point with IAT sensor, but I am ignorant of when ECU steps in. I would think it would be able to avoid it.
It sounds simple to undo TSB then. Just shut the bypass and have a good day!
So we agree stock IC with blocked grille will be just a wee bit hotter. Not much, never gonna notice. But higher IAT's offer less power at same boost. Can we agree on that? Now how much, just higher or lower.
Now add the TSB. It isn't bypassing the outside, if I understand correctly. It is just bypassing the coil(internally...important). So the size of your IC coil is smaller and you said it bypasses 80%??? If so that's crazy if it that thing ever sticks open when it's 100degF you are at full boost and your intake has malfunctioned.
100F air pressurized to 25psi....That has to get pretty hot right. I need to get my charts one of these days. Anyway, my point is. At 25psi, it's going to be HOT! If that bypass stuck, 80% of IC is not helping get rid of it. If your intake manifold is failed (which is why the IC kit is in there to begin with...just pretend Intake flaps are stuck shut.), then you have NO airflow. No air = no air out. I hope you are on the train already, cause this heat train just went down a hill with no brakes.
No air out is important. x volume of intake=x volume of exhaust. Can we agree? That is a valid equation? We have the variable of fuel, but just to make it easier in discussion, let's say coasting down a hill in gear...so fuel is removed from equation for now.
If we agree that equation is correct, let's play with it.
100cfm in = 100cfm out. Check mark, smiley face
50cfm in = 50cfm out. Check mark, smiley face
Ok, now let's complicate it just a bit.
Let's give some value of heat to the cfm, tells us useful info for volume, we don't know if it's 100F or 1000000000F.
Let's just say 1:1 cfm to joules. Keep everything constant in the environment.
So 50 cfm has 50 joules, 100 has 100, etc. I'm just trying to show the heat flow, heat in = heat out minus losses.
So if we flow more air we can carry more heat. Bigger exhaust, it gets out faster. But we have a problem? If what I said was correct, then my exhaust should be 100 joules. Let's just call it 100F, the intake air temp. It's definitely way hotter. Oh that's right the fuel!
We took that intake air, boosted it at 100F to 25psi. We took 80% away from IC if bypass sticks. So what we can't remove stays on the heat train.
So god only knows how hot that intake air is. Now add fuel, with very little air because of a bad intake manifold. You have a rich mix, afterburn, high egts. Bad stuff yo! Unless you went to a tuner and had something taken out. Once that is gone, you can get rid of all that heat, with it, it's got nowhere to go (of course some loss but mostly inside exhaust piping) for a while...Low pressure egr stuck open, with a malfunctioning egr cooler....Rut row. That's some hot stuff going straight into an IC that we already agreed is much less efficient with bypass open. Exhaust flap stuck closed....it's like driving over the GW bridge trying to get out. If everything goes right, it's ok, but too many cars(heat), especially when you keep adding them, can't go anywhere if you keep closing lanes and exits. You get a pile up of heat. Watch a rush hour traffic jam....It builds and go backwards. Always more heat towards the end of the restriction. But if you don't clear the traffic ahead, and keep adding cars, eventually you get gridlock. No movement of HEAT.
So let's think about detonation. I only brought it up, because I swore in the IC thread I read someone say they detonated, but I, like you, said no way....But the code you diagnosed got me thinking. And you saying 80% only strengthened my suspicion.
Covering up a car with TSB can REDUCE efficiency enough to trigger a CEL. What happens when it's hot? Now this is where I would think ECU would step in at some point with IAT sensor, but I am ignorant of when ECU steps in. I would think it would be able to avoid it.
It sounds simple to undo TSB then. Just shut the bypass and have a good day!
VeeDubTDI
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It will solve your intercooler efficiency problem.
Ha, you are correct lol
Anyway, the code went away the same day I took the covers off so it was definitely them. I'm just going to try the upper cover to see if it helps retain some heat. As it is I need to run a gear higher to keep any heat in the cabin. It was 25F on the way home today and I had to keep the RPMs around 2200 to maintain heat...
Samcar222
Veteran Member
So correct me - if it is above freezing (when my IC TSB is in-active) and I'm running the IDparts lower block for the sake of slightly faster warmup, less road grime, etc, that's perfectly ok, but when the TSB is active, the lower grill should be open? Should I use the upper two blocks below freezing when the TSB is active, leaving the lower grill open? Explain a bit if you could, thanks in advance.
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I've personally given up on using my lower cover, as each time I put it on, the car gives me the code again. So for now I have just been using the uppers, but not sure if they are even really doing much to help. I was hoping the covers would be more effective, but it just hasn't been the case for me.
mrutter1
Veteran Member
My car threw the code last night. I cleared it with my ScanGuage II and searched the web for the code which brought me here...go figure 
. I was all covered up front with both upper and lower covers; driving in 38 degree mist. I love my covers and run them at 45*F and below. I closely monitor EGT's and water temp with my ScanGuage. I did see one time where the temps rose to 226 and then it dropped back quickly to 198-202...I believe the fans turned on, meantime the dash needle remained on 190. The car has the TSB and still gulped water occasionally, but not once since using the idparts winter front.
. I was all covered up front with both upper and lower covers; driving in 38 degree mist. I love my covers and run them at 45*F and below. I closely monitor EGT's and water temp with my ScanGuage. I did see one time where the temps rose to 226 and then it dropped back quickly to 198-202...I believe the fans turned on, meantime the dash needle remained on 190. The car has the TSB and still gulped water occasionally, but not once since using the idparts winter front.
tydaddy
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I've got the same issue...about 2 days after installing winter fronts, I got the same CEL. Difference is I still have the Stock IC...and temps haven't been THAT low...mid 30's...40/50 during the days.
cevans
TDIClub Enthusiast, TDI Parts Ninja Vendor , w/Bus
Took me too long to find this thread. Thanks everyone for sharing their information.
I'm really wondering what is the X factor that is making some cars react and others not. I haven't had any issues with any of the cars in MA that I monitor on a daily basis. But clearly some cars are being a problem. We've sold nearly a thousand covers for this model and haven't had anyone call and complain about this issue, so I don't believe it is widespread.
YukonLT - would you be willing to do some testing? I'd like to send you a few lower covers that are cut to allow more airflow into the engine. The idea being to find the "sweet spot" of keeping heat but allowing the IC to work. PM me if you are!
I'm really wondering what is the X factor that is making some cars react and others not. I haven't had any issues with any of the cars in MA that I monitor on a daily basis. But clearly some cars are being a problem. We've sold nearly a thousand covers for this model and haven't had anyone call and complain about this issue, so I don't believe it is widespread.
YukonLT - would you be willing to do some testing? I'd like to send you a few lower covers that are cut to allow more airflow into the engine. The idea being to find the "sweet spot" of keeping heat but allowing the IC to work. PM me if you are!
I could do that. I will PM you.
VeeDubTDI
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I think radiator air is recirculating through the intercooler when the winter covers are attached in some situations. Some folks have mentioned the exterior temperature sensor reading unusually warm, as well.
A similar phenomenon happens on my buddy's F-450 with the snow plow on the front - it reverses the flow of air through the radiator in some conditions when the fan isn't running, which makes the exterior temp sensor and the automatic HVAC go haywire.
A similar phenomenon happens on my buddy's F-450 with the snow plow on the front - it reverses the flow of air through the radiator in some conditions when the fan isn't running, which makes the exterior temp sensor and the automatic HVAC go haywire.
VeeDubTDI
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I think radiator air is recirculating through the intercooler when the winter covers are attached in some situations. Some folks have mentioned the exterior temperature sensor reading unusually warm, as well.
A similar phenomenon happens on my buddy's F-450 with the snow plow on the front - it reverses the flow of air through the radiator in some conditions when the fan isn't running, which makes the exterior temp sensor and the automatic HVAC go haywire.
A similar phenomenon happens on my buddy's F-450 with the snow plow on the front - it reverses the flow of air through the radiator in some conditions when the fan isn't running, which makes the exterior temp sensor and the automatic HVAC go haywire.
mrutter1
Veteran Member
Diesl,
Please explain to me how to read my intercooler temp with my ScanGauge II.
Thx!
Please explain to me how to read my intercooler temp with my ScanGauge II.
Thx!
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Diesl
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Marshall, it's in the first link in my signature:
For ICT TXD is 07DF0177, RXF is 04410577, RXD is 3008 and MTH is 00010001FFD8 for ºC. For °F, you need to multiply by 9 and divide by 5. -40 is the same in °F and °C, so the FFD8 stays. So that would be MTH 00090005FFD8.
For ICT TXD is 07DF0177, RXF is 04410577, RXD is 3008 and MTH is 00010001FFD8 for ºC. For °F, you need to multiply by 9 and divide by 5. -40 is the same in °F and °C, so the FFD8 stays. So that would be MTH 00090005FFD8.
mrutter1
Veteran Member
awesome...thanks! I'm a little rusty at programming xGauge in my ScanGauge, but it is coming back to me now. the C to F conversion is very helpful.
Draz
Member
I got the same code a couple of months ago, I don't have the TSB mentioned, and am fully stock. I got the code with all covers on and after clearing the code and removing only the uppers it hasn't come back. Outside temp when the code popped up was about 25-30F