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Ive ruled out IC boots and IC leaking. I've replaced the vacuum line from intake manifold to oil pressure regulator.
Ive seen people discuss the BPV, throttle body, charge pipe, and even intake tube as possible sources but all of these are before the compressor, so that seems illogical unless there's a vacuum line running from the downstream side of the compressor back to one of those components.
My first question is-does anyone know where the computer is pulling the readings from that it compares to drop a P1498 code?
It would seem to me that the leak has to be at the SC discharge horn, an IC boot, in the IC itself, or at the intake horn or intake gasket to the head. Or I have a bad sensor that's throwing off the reading.
My guess would be that it thinks it's seeing unmetered air at the TMAP in the intake manifold, and therefore the leak is probably somewhere between the MAP and the TMAP but not necessarily after the supercharger. Just a guess though since I'm not really an R53 guy.
So I don't have an r53 but I like those diagnostics challenge, I'll chime in.
"Unmetered air" to me sounds like either:
- a sensor is bad. Looking up the code it's the TMAP sensor, as deepgrey said, which can go bad. Check it's properly connected, and apparently it can become dirty, and cleaning it can give you a short time lease before it fails again, found here.
- air is leaking from somewhere. While you replaced/checked some parts, did you do a smoke test? Have a shop do it if you don't have the tools for it. Recommandation found here.
To further qualify where my thought process is going, my assumption is that you don't have any lean codes, so the DME is presumably getting the fueling calculations right somehow. I was assuming that the DME uses the MAP and the TMAP to calculate air mass somehow and was seeing an inconsistency between the two somehow. Now that I've had time to sit down at my computer, the factory docs aren't particularly illuminating as to how exactly the DME uses the MAP and TMAP, but they do say
On the MINI COOPER S the pressure differential is measured across the supercharger to determine the manifold air density. To measure this differential two sensors are fitted, one on either side of the supercharger.
A TMAP sensor is fitted on the intake manifold pressure side (after the supercharger) and has the same function as the TMAP on the MINI COOPER. The difference is that this sensor has a maximum pressure range of 250 Kpa (36.25943psi).
Another TMAP sensor is fitted upstream of the supercharger and measures the pressure between the supercharger and throttle plate. This sensor is exactly the same part as the MINI COOPER TMAP but the temperature sensing capability is not utilized.
TMAP Sensor:
The TMAP sensor is located in the intake manifold where it is exposed to higher than atmospheric pressures as produced by the supercharger. The MAP sensor is located between the supercharger and the EDR, a location not effected by additional pressures from the supercharger. The first job of the MAP sensor is the measurement of the barometric pressure. When the ignition key is placed in the "ON" position (Main Relay powered up), the sensor reads atmospheric pressure (High Voltage) because the pistons are not moving yet.
Second, it measures the absolute pressure in the intake manifold. Absolute pressure is barometric pressure minus the vacuum created by the pistons. So, if the barometer is reading 1.5 Bar at sea level and the manifold vacuum (gauge) is 1.0 Bar at idle, the manifold absolute pressure would be .5 Bar.
The EMS2000 compares the voltage from the TMAP sensor (ahead of the supercharger) to the voltage received from the TMAP (after the supercharger) and calculates air volume drawn into the engine.
Voltage Reading of .6-1.5 volts indicates high vacuum condition (Idle or no load)
Voltage Reading of 4 volts indicates low vacuum condition (Full Throttle)"
It doesn't answer your question exactly about which sensors the DME is pulling data from to throw the code, but it seems like the only possibilities are the MAP and TMAP (and I guess the O2 sensor, but wouldn't that show up as a lean condition?).
I found the DTC pdf. My copy just has simple compressed images for the figures, so it's hard to read, but it appears to say for P1498:
Air intake system leak - block 3.
Monitor strategy description: Comparison of modeled mass air flow at cylinder and mass air flow at throttle.
Primary malfunction criteria and signal: Modeled MAF difference adaptation exceeds threshold relative to throttle opening.
Based on the DTC description, I think I'm on the right track with the leak being between the MAP and the TMAP. Or at the very least it's between the throttle body and the TMAP. I can't remember which side of the throttle body the MAP is on since I haven't messed much with R53s.
Last edited by deepgrey; Mar 27, 2023 at 12:40 PM.
Reason: found DTC pdf
To further qualify where my thought process is going, my assumption is that you don't have any lean codes, so the DME is presumably getting the fueling calculations right somehow. I was assuming that the DME uses the MAP and the TMAP to calculate air mass somehow and was seeing an inconsistency between the two somehow. Now that I've had time to sit down at my computer, the factory docs aren't particularly illuminating as to how exactly the DME uses the MAP and TMAP, but they do say
It doesn't answer your question exactly about which sensors the DME is pulling data from to throw the code, but it seems like the only possibilities are the MAP and TMAP (and I guess the O2 sensor, but wouldn't that show up as a lean condition?).
I found the DTC pdf. My copy just has simple compressed images for the figures, so it's hard to read, but it appears to say for P1498:
Based on the DTC description, I think I'm on the right track with the leak being between the MAP and the TMAP. Or at the very least it's between the throttle body and the TMAP. I can't remember which side of the throttle body the MAP is on since I haven't messed much with R53s.
This is a huge help!!!
I'll dive in later when I'm off work, but depending on MAP position it could introduce several other possible leak sources.
First I'm going to pull both sensors and clean them to see if that helps. If the problem persists I'll start working through the possible leak sites. Smoke test would make it easier, but I don’t have a good place to do it for me, I don't have time to build a DIY tester, and the purpose built ones are more, than I want to spend.
I'm not getting a lean code--at times I am getting a too rich code. Not, sure how, to interpret that--I assumed it was a boost leak, so not as much air getting to the combustion chamber as planned, making it run rich?
Ohh. Can "unmetered air" also encompass boost leaks? If so, I guess there are more possibilities. I'm more used to NA engines, so I guess I have a tendency to think in terms of vacuum leaks.
I was hoping someone would pop along who has more experience in how the DME is modeling airflow, since it has to back out the air mass calculations indirectly. That would make clearer what the DME is comparing between the two sensors to set the DTC - I just don't understand exactly how it's modeling airflow and how various issues would manifest. It's probably something obvious that I don't remember about speed density.
edit: Hah, of course it could be boost leaks, right? I'm not sure what I was thinking. It would see still a difference in the calculated air masses, and that's what you've already checked.
Last edited by deepgrey; Mar 29, 2023 at 03:24 PM.
Reason: being stupid
Started to pull the sensors after work last night to clean them, then decided to wait since I was leaving this morning for a 3 day work trip, and that is the PERFECT scenario for a super simple task to become impossible. You know-every fastener falls into the most impossible location, the wires pull out of the connector, and then the second sensor spontaneously combust 30 seconds after the auto parts store closes.
Nope-not gonna get this guy that easy. I'll wait til the weekend. 😂
I just posted a possible culprit to this thread-R50/53Vacuum leak P1498? I had the IC fail on me.
Thanks for this. I swapped my stock IC back on and ruled out IC in my case, but it could definitely be a point of failure that could cause, this fault.
Thanks for this. I swapped my stock IC back on and ruled out IC in my case, but it could definitely be a point of failure that could cause, this fault.
Any update on this? I'm tracing the same issue. It drives me insane
Have been plagued with this issue myself several times. My issue is the supercharger intake duct not wanting to full seat against the supercharger, which throws this code periodically. Solution for me, install the gasket on the supercharger first, then force the tube onto the supercharger. When working solo i force the intake tube towards the supercharger with a pry bar as the yellow arrow below points, you want to make sure you have a consistent gap along the bottom between the two pieces where the yellow line is.
Have been plagued with this issue myself several times. My issue is the supercharger intake duct not wanting to full seat against the supercharger, which throws this code periodically. Solution for me, install the gasket on the supercharger first, then force the tube onto the supercharger. When working solo i force the intake tube towards the supercharger with a pry bar as the yellow arrow below points, you want to make sure you have a consistent gap along the bottom between the two pieces where the yellow line is.
Maybe yours can be as simple as this?
(disregard red writing, taken from another post)
I did SC service myself 20k ago. It was all good until this year. Started coming back on only when it's cold outside and coming to a stop closer to idle. I found one leak that I fixed. It was the map sensor fitting broken and previously fixed with a piece of airline hose. I fixed that. Now that part is leak free. When I smoked test the system, smoke was coming up from charge pipe area. I sprayed soap and water spray and breather tube fitting was bubbling. I looked at it and the plastic tube is not sitting flush where to the ridge. No matter how hard I push it won't go in. It does lock though. I can pull it out by pressing on red locking tab but when i insert it it sits about half inch away from the ridge.
I remember breaking one of them red retaning clips on a previous charge pipe, the tube wouldn't sit flush back down (what i think your talking about). I used some E6000 to seal around the outside of the tube. Was not fun when I replaced the charge pipe later but served a purpose!
100% a leak in the supercharger charge pipe will throw P1498. The one vacuum plastic tube coming off the charge pipe goes directly to a MAP sensor, the other to the valve cover (if i remember correctly). The R53 uses two MAP sensors however, the second map sensor is on the intake manifold direct front of the engine after the supercharger.
So essentially, car the is now having conflicting numbers between the two map sensors. Pre supercharger and post supercharger readings are conflicting one another hence P1498. I do believe this has been a common misconception regarding it having to be post supercharger, as the direct meaning of this code relates only to "unmetered air is entering the system". Somewhere over the years it was believed to only be post supercharger, although you can find countless forums about charge pipe issues causing this.
If your clip is not broken, or the plastic vacuum hose isn't damaged. You can try replacing the red plastic retainer, you could replace the vacuum line, you could replace the entire charge pipe. Again i solved this on an older charge pipe with some E6000 goop to seal the vacuum line until i later replaced the charge pipe and vacuum line when swapping the engine. Best of luck!
100% a leak in the supercharger charge pipe will throw P1498. The one vacuum plastic tube coming off the charge pipe goes directly to a MAP sensor, the other to the valve cover (if i remember correctly). The R53 uses two MAP sensors however, the second map sensor is on the intake manifold direct front of the engine after the supercharger.
So essentially, car the is now having conflicting numbers between the two map sensors. Pre supercharger and post supercharger readings are conflicting one another hence P1498. I do believe this has been a common misconception regarding it having to be post supercharger, as the direct meaning of this code relates only to "unmetered air is entering the system". Somewhere over the years it was believed to only be post supercharger, although you can find countless forums about charge pipe issues causing this.
If your clip is not broken, or the plastic vacuum hose isn't damaged. You can try replacing the red plastic retainer, you could replace the vacuum line, you could replace the entire charge pipe. Again i solved this on an older charge pipe with some E6000 goop to seal the vacuum line until i later replaced the charge pipe and vacuum line when swapping the engine. Best of luck!
So air pissing though the breather tube then will definitely trigger the code.
My understanding or maybe I'm over thinking, because looks like i had two leaks. One at the map sensor and one at breather tube and it wasn't setting the code because it sensed same type of pressure?
Now when i fixed the map sensor leak from the plastic tube, pressure variation is different and it's triggering the code right away.
I replaced the charge pipe gasket last year. The ear where the 10 mm mount bolt goes was broken so i made a little metal bracket (serves as a washer just longer on one side to press on the rest of the bracket that's left) and tightened the bolt so it holds.
How do you manage to push the breather hose all the way down to the ridge? It won't go in no matter what.
Sounds like your on the right track. Based on it reading before and after supercharger all vacuum leaks matter.
Them stubborn red clips, push down and pull the hose out at the same time. Reverse to install, if the hose still won't go in all the way I could only suggest to replace the red clip as it could be damaged inside. This is of course after inspecting the plastic hose end for any kind of damage.
If replacing the clip still won't let it seat, and the plastic hose is fine I could only suggest some sort of goop to seal it unless replacing the entire charge pipe. Personally I'd just goop it!
Sounds like your on the right track. Based on it reading before and after supercharger all vacuum leaks matter.
Them stubborn red clips, push down and pull the hose out at the same time. Reverse to install, if the hose still won't go in all the way I could only suggest to replace the red clip as it could be damaged inside. This is of course after inspecting the plastic hose end for any kind of damage.
If replacing the clip still won't let it seat, and the plastic hose is fine I could only suggest some sort of goop to seal it unless replacing the entire charge pipe. Personally I'd just goop it!
Cheers!
I know how to release the hose. It comes out when I press on the clip. When i push the hose in, it stops and if you were try to remove it again it won't come out (locked). Just won't go all the way in.
Isn't that a rubber seal underneath the red clip and or the red clip has an oring inside?
I'll try it one more to push it back in using longer screwdriver pushing on the clip and 90 needle nose pliers grabbing the tube pushing it in while pulling rad hose.
Sorry @DA93 been looking for an answer. It seems there is an internal seal, as relayed on this forum below. Land rover apparently makes a replacement clip!
