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2000 acura tl
236k miles
Tranny rebuild at 175k miles
While driving up a steep incline in d5 (driving through mountains on way home to Las Vegas, NV from Laughlin, NV), 2 engine light codes illuminated: P1739 (3rd clutch pressure switch ) and PO401 (insufficient egr flow).
My Gameplan: purchase and replace pressure switch and perform transmission flush or drain and fill. Purchase and replace egr valve and clean egr ports.
Note: egr valve was replaced about 12 months ago, along with egr port cleaning. Was surprised seeing this code. Note: transmission fluid has been drained and filled a few times in 2023. My fluid is not low nor old. Note: even with these lights on, I have ZERO performance issues or misfires or shaking or slipping or banging. Car runs perfect. Very confusing.
I know my TL hates going up mountain inclines. But after pulling over and clearing the codes, it ran perfectly (just like it did when the lights came on) codes came back on this weekend.
Thoughts on my gameplan? Do you think my transmission is on its way out? With these codes, why ZERO performance issues?
Domenic, I would have to assume that the fluid moved when the car was on an incline causing the sensor to trigger. Did you check the fluid level to make sure it was full? Part number 28600-P7W-003 has been replaced by 28600-P7W-013.
have you checked and cleaned out the EGR passageways in the upper intake manifold? Those cutouts under the metal gasket are part of the EGR system, if they get blocked it will trigger the EGR code. I would open up the upper intake and check and clean out if you haven't done so recently. I would also replace the gaskets (intake and throttle body) if you remove the upper intake manifold cover.
Domenic, I would have to assume that the fluid moved when the car was on an incline causing the sensor to trigger. Did you check the fluid level to make sure it was full? Part number 28600-P7W-003 has been replaced by 28600-P7W-013.
have you checked and cleaned out the EGR passageways in the upper intake manifold? Those cutouts under the metal gasket are part of the EGR system, if they get blocked it will trigger the EGR code. I would open up the upper intake and check and clean out if you haven't done so recently. I would also replace the gaskets (intake and throttle body) if you remove the upper intake manifold cover.
I checked the fluid when I got home and it appeared full to me, also clean and smooth. But the tranny stick always gives me a hard time. My eyes aren't what they were. The other night after clearing the codes, I was driving in D4 and then when on the highway i put it in D5. within a few minutes, the codes both came back. I think it's weird that both codes come on as they are not related. But anyway.....
I'm going to clean the egr valve and take up the top plenum plate and clean what I can. I don't want to pull the entire I take manifold (bottom) up myself.
Just weird that if my fluid was low or if the switch was bad, why wouldnt car slip or bang or whatever?
Just checked tranny fluid again....full. perfect.
I rather not pay $120 for the pressure switch but if the code keeps coming on.........
if it comes on for a third time, ill replace.
guess need a rental car next time i drive downstate (up and over the mountain)
I can speculate that the fluid moved away from the switch, it is mounted on the front side which when going uphill would be at a high point. That switch should be a lot cheaper than $120. Have to think about the D4-D5 causing the code. When you are on the road what gear do you normally use? How fast are you driving and what are the RPMs?
Have you tried checking the wires that feed into the plug for that switch? when I replaced my transmission I noticed that the plug doesn't hold the pins that terminate the wire harness there. plugging the harness into the switch pushed the pin out of the plug and as a result connection was poor.
On a side topic of part numbers: I have a different part number (28600-RKE-004) on the pressure switch and it's working great for me...seems like this other guy received a different part number from the dealer as well.
Coincidentally; that part number is also used on the AV6 transmission.
would be interesting to see the difference between what Jon has and mine....I think they are probably measuring a different setpoint in terms of pressure .
Strange, I see your part number ((28600-RKE-004) but the Acura part site says it doesn't fit a 2000 TL. Although, I agree that it is probably a difference in pressure setpoint. I also agree that you should always check the pins in any electrical connector before you plug connectors together.
Purchased honda oem clutch pressure switch. The part has been updated, it has a new part number.
Replaced part. Electrical connection looked well and clipped on solidly (nice clipping sound)
Added some dw1 honda fluid. Checked level. Perfect.
Cleaned egr valve. Pulled upper plenum plate and did a poor man's cleaning. (I did not pull up the top intake manifold; i just dont like messing with it).
Test drive was solid. If it drove any better I would think something was wrong. Seemed like it shifted better (though it was fine before) - maybe just placebo affect?
Thank you, guys! Much appreciated! When I have an issue with the Acura, I first thing to go on Acurazine for help!
Ok, so. Drove the car last evening. Even went from D4 to D5 while on the highway. I usually stay in D4. Mostly I am in D4. The only time I go into D5 is when I go on the highway or interstate, and I switch to D5 when I get to 60mph. Been doing this for years. Never an issue.
Anyway. Transmission code did not come back on. BUT..........the EGR code came back on, and kept coming back on (after I cleared code). PO401. So.....maybe I do need to pull the top intake manifold off and do the proper cleaning and/or maybe I need to get a new EGR valve. I want to say....no stalling. No missing. No rough idle. No chugging. Runs perfect. I would think if the EGR passage was blocked that bad, I would get problems with performance. Odd. Thoughts?
If the tranny code stays off, I'll be happy. EGR thing I can deal with and ultimately fix. Much cheaper than $3k rebuild of a tranny!
I hope you have a copy of the service manual, you can find the troubleshooting of your failure on page 11-197. If you need the PDF of the manual you can get it HERE.
PO401. So.....maybe I do need to pull the top intake manifold off and do the proper cleaning...!
just checking...It's more than the intake manifold. if you remove the EGR, there is a passage that loops down beneath it and up through the intake runner. it tends to get carbon built up in it as well. I needed to use a pip cleaner and lots of carb cleaner.
I think I am going to return the MAP sensor. Thinking if it was the MAP sensor I would have noticeable performance issues. I have zero issues right now.
I'm going to take car to mechanic (due for oil change anyway) and ask him to rssolve the code, by most likely, cleaning the port/clearing the blockage. He's done it before and can do it alot better and faster than me. Stay tuned!
The 3rd clutch pressure switch error code has not come back since I changed the switch. Good news!
now, a new code: p1676 (abs light also came on) vegas got some rain the other night and I went over a deep pool of water....wondering if I shorted something. Ughhhhhh.
If you were driving through puddles water got somewhere. Clear the code and check when everything is dry. You can inspect the cables and the connectors. If it comes back when dry there is a TS procedure on page 11-134 of the manual.
Do you work as a Cooler for a casino?
All dry and cleared the code, but it came back. However, gonna wait and see if it comes back this weekend. Give it a few days to see.
Not a casino cooler, just a bingo, keno, poker, and slot fan. 😀
If you were driving through puddles water got somewhere. Clear the code and check when everything is dry. You can inspect the cables and the connectors. If it comes back when dry there is a TS procedure on page 11-134 of the manual.
Do you work as a Cooler for a casino?
when you say check cables and connectors, where do I look? What am I looking for?
Start looking at the connectors and cables at the ABS brake connectors. If you look behind the wheels on the knuckles that hold wheel bearings, rotors. etc., you will see a wheel speed sensor that has a cable snaking around going up through wheel well by the side of the upper control arms. Look for damaged wires, cracked connectors etc. keep tracing the wire bundles back to see if you can find anything. Check around the speed sensor for cracks in the plastic where the speed sensor goes into the hole that holds it in the knuckle and work back into the engine compartment.
Yesterday I properly cleaned the EGR port, as shown in the videos online. It wasn't too bad. I was careful and made sure I didn't drop anything down into the engine. Honestly, the port wasnt "clogged". Yes I was able to clean out some carbon or grime, but considering this was done last year, it wasn't as bad as I've seen on videos. I cleaned and emptied a whole can of cleaner into the port. Wire brush. Flat head screw driver. More cleaner. Cleaned the egr valve again and the ports under the egr valve. I do not believe it could be any cleaner.
took it for test drive, and it drives PERFECTLY. sounds perfect. Perfect idle. No noise. No miss. No chugging. Then......CODE CAME BACK.
So after getting ticked off I purchased a new EGR valve. Because at this point, why not. Cleared code. CODE CAME BACK. (Still no tranny code or the abs/TCS code). I have no idea what to do next.
Maybe MAP sensor?
But.....if MAP sensor was bad, would i not have major performance issues? Wouldn't that present a different code? Really trying to handle myself versus taking to mechanic but......
help!?!!
Thanks!!!!!!!
Did you find a suitable pipe cleaner and run it through the lower portion of the intake system that I circled in red above? That port should curve down to the right and loop up into the EGR port.
A coat hanger is too rigid to fit in there I needed to use pipe cleaners suitable for cleaning reusable straws to get in there from both ends; when I did: carbon caked that running brake or carb cleaner alone would take tens of cans to erode away.
I did not go down far enough for it to reach the egr port on the egr valve housing. When I sprayed the cans down into the upper port. (your photo), i noticed cleaner bubbling up from the round opening on the egr valve housing. Maybe I need to try this again with a superior pipe cleaner and ensure it goes from top to bottom of port openings.
Did you find a suitable pipe cleaner and run it through the lower portion of the intake system that I circled in red above? That port should curve down to the right and loop up into the EGR port.
A coat hanger is too rigid to fit in there I needed to use pipe cleaners suitable for cleaning reusable straws to get in there from both ends; when I did: carbon caked that running brake or carb cleaner alone would take tens of cans to erode away.
but even if I didn't clean it perfectly, wouldn't what I did make ANY positive impact? I mean, it's better now, right? Any chance this is MAP sensor (I could clean that too )?
If you have a blockage in the passageway and your cleaning efforts did not reach the blockage it may not clear it up, in fact it could make it more compacted. The safest way to eliminate possible causes is to take one possible cause at a time and completely finish eliminating the possibility. In this case since you can't see it and others have had issues deep inside you should probably try to get further with cleaning the passageway before moving onto the MAP sensor. Do not use brake cleaner or gumout to clean the MAP sensor, there is a different specialized cleaner for the MAP sensor as the others can corrode the platinum wire that is inside many of the MAP sensors.
As Whitetiger5 said I used something similar like the picture below. I remember getting several different ones to find ones that would fit through, I also put one on a drill and used that to help clear it out.
I'm going to home depot today to investigate some pipe cleaners / drain cleaners.
IF i needed to get a MAP sensor, is it safe to assume that i should purchase from Honda, or could an aftermarket cheaper brand be OK? I saw one on rockauto.
part 37830-P8E-S00 = about $80 from honda after searching online.
Domenic, I am not sure if this is one of those parts that should be OEM. Sometimes I try parts from aftermarket makers and they are OK and sometimes not. When I do try aftermarket I usually use SMP or WVE. On this part there is an O-Ring that should be replaced when you replace the part. P/N 16075-P07-000 it is 9.8x1.9mm. Maybe others here can say if they have any experience with an aftermarket MAP sensor.
Mechanic checked egr port. It is not clogged. Clean and good. Said need honda egr valve. Said to take autozone egr valve back for refund. Said buy part from honda or try junkyard. I'm on the case.
Mechanic checked egr port. It is not clogged. Clean and good. Said need honda egr valve. Said to take autozone egr valve back for refund. Said buy part from honda or try junkyard. I'm on the case.
Back from junkyard. Bought used egr valve. Cleaned it up. Installed. Will see what happens this evening. Mechanic said he feels the autozone egr valve is crap and need oem part. Said could be pcm if this continues. But I don't get any other weird codes or other troubles so.....
Code came back on. Not sure what to do. Guess I could ignore it but I think it may be affecting gas mileage or maybe even performance. Plus, won't pass inspection with a check engine light. Ughhhh.
Sounds like you may need to replace the EGR valve...did you keep the old one?
I keep reading online that issue could be the MAP sensor. I see folks referring to it as a dpfe sensor.
when at junkyard yesterday, i grabbed a map sensor just for the heck of it. I put that one on the vehicle, but code still comes on.
Besides a blockage (which I don't have) or a bad egr valve (which i doubt I have), is there any other mechanism that could be telling the pcm that there is insufficient flow? Like a vacuum issue? An evap line? Evap sensor?
Below is a picture of the EGR system. You can see it in the manual. Did you look through the manual? As you can see it is pretty much stand alone. You can also find the EVAP system components in the manual. If the EVAP system had a problem it should have issued another code (P1457). The only thing those two systems have in common is the PCM.
EGR System.
The system description does mention input to the PCM from "other sensors" but so far I haven't found which ones, I imagine it is all of them, Try looking further in the manual and see if you can identify any of them.
You also might try disconnecting the battery for a while and see if that clears the PCM memory.
Below is a picture of the EGR system. You can see it in the manual. Did you look through the manual? As you can see it is pretty much stand alone. You can also find the EVAP system components in the manual. If the EVAP system had a problem it should have issued another code (P1457). The only thing those two systems have in common is the PCM.
EGR System.
The system description does mention input to the PCM from "other sensors" but so far I haven't found which ones, I imagine it is all of them, Try looking further in the manual and see if you can identify any of them.
You also might try disconnecting the battery for a while and see if that clears the PCM memory.
Thank you, sir. Sorry, I been going goofy over this. My apologies.
Will try resetting the pcm by disconnecting battery cables and placing them together for a while. Guess this clears the pcm better than clicking "erase codes" on the engine light reader?
Would bad pcm present other issues?
At this point, maybe I need to purchase NEW OEM HONDA egr valve and map sensor. thats about $325. Yikes. I know used pcm is about $30 plus install/programming.
Just doesn't make sense. 2 egr port cleanings. Mechanic inspects egr port and says no issue. I try a multitude of egr valves. Even swap a map sensor. Same light.
11-13-2023, 12:29 PM
