Honda P1129 MAP Sensor Tips - HOLD FIRE On Parts Cannon!!

In this video, I show you some things I look for when diagnosing a Honda P1129 code, which is a MAP Sensor signal higher than expected. Symptoms included rough idle, stalling and the vehicle was in limp mode which meant it could not go over 2800 RPMs (approx). The exact vehicle in this video is a 2003 Honda Civic EX.
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[@BigDog50001]

Don't fire parts at check engine codes! Link to The Mech a nic Channel: bit.ly/2HxP0Vg Be sure to subscribe for more tool and car repair videos! kzbin.info twitter.com/BigDog50001 instagram.com/bigdog50001/ Disclosure: This channel earns a small commission using some of these links - at no additional cost to you. The Big Dog 50001 Automotive Channel Store can be found here: www.amazon.com/shop/bigdog50001automotive

[@jonathanruiz1543]

I got this code after I cleaned the throttle body it was now seems to be richer aka accelerating. I got the map code with the check engine light on it’s like when I hit the breaks it revs making my car run rough I have a Honda element any suggestions P1129

[@jarana10]

Hello I have the same code and symptoms . Could you fixed your car ?

[@jonathanruiz1543]

@@jarana10 yes fuel injector had to be replaced

[@Borkowski.R]

2009 Honda Accord with MAP error code P1129, rough idle and limp mode (won't go past 3,000 rpm). The solution in my case was engine valves adjustment (intake and exhaust valves). Things I have done to the car that failed to solve the above issue, replaced engine oil, new timing chain, replaced VTEC Solenoid module, replaced Variable Valve Timing solenoid, replaced PCV, cleaned throttle body, checked for vacuum leaks.

[@BigDog50001]

👍

[@thanoswasright4869]

I have this code and also everything is lite up on dash,tire check,power steering,tpms check system,vsa system,hill start.the battery was dead so I'm hoping it's just the computer had to reset.

[@Longtrailside]

I was teaching this same thing to my nephew on his honda, though it was a different problem. Great job!

[@BigDog50001]

Longtrailside Thanks, I hope he listened to you!

[@Longtrailside]

Big Dog50001 Automotive He did. I try to teach him how I was taught years ago. Verify the problem , then replace, then confirm the repair. He learned this the hard way when his dad helped him on his first car and never verified or confirmed the repairs, just threw the parts cannon at it and then didn't confirm the repair. I.E. put new alternator in and didn't put the plug in, and left him stranded at the store. He follows how I teach him now, and doesn't want his dad to work on his stuff now, due to to many bad repair jobs and parts he didn't need to buy.

[@nathanield.4527]

Awesome videos! The best part is that you respond to questions. 👍

[@BigDog50001]

Thanks for the comment!

[@Mawcxs]

I have the same error code. when i put my car in neutral or hit my brakes/ or am completely stopped, my engine will rev up and will go up and down from there. what can i do? thank you

[@201950201950]

Perhaps this is the problem that I am having. I have a 2015 Honda Civic CNG. I guess with these specific civics they recommend to have the valves adjusted I've never had them adjusted and it's at 130k. Recently it has been idling kind of rough. I've had the car while it's at 13000 me so I had my mechanic clean the throttle body. He said the tube that extends between air box and the throttle body had a crack so we changed it then after that I drove it home and the next day there was a Christmas tree of death. I took it back. he ran a scan and asked for the map sensor to be replaced just like the code in this video. The problem persists. Now after watching this video I have a better idea and I'm using a different mechanic

[@TheDhares]

I have the same issue, code p1129 in a honda civic 2013 lx, the same crack in the tube, i already change the map sensor and the problem continued. Let me know how could you solve this problem?? Please

[@arianaz2566]

​@@TheDharesI do as well. Any ideas on what it is?

[@lukegnanapragasam9070]

What does ps value on Civic 6th gen map sensors stands for ( ps33 / ps30 )

[@BigDog50001]

If you are talking about numbers on the actual MAP sensor itself, they are most likely model/rating numbers and the PS stands for Pressure Sensor. I only recommend Honda MAP sensors, they are a critical input component for the engine computer and Hondas don't like cheaply made aftermarket ones. If you are talking about scan tool info, the Manifold Absolute Pressure (MAP) Sensor does just what the name implies, it senses pressure inside the intake manifold. When looking at live data of a Honda MAP sensor on a scan tool it will show the pressure reading as either PSI or kPa (English or Metric). Newer Honda systems will show both voltage and pressure readings on a scan tool.

[@fernandomendoza9919]

Just found your channel. Great video!! Straight to the point, nothing but valuable information. I HATE other videos where they’re trying to be personalities, repeat same info over and over, they start talking about how their days is going aaagggghhh!!! I want to pull my hair out!!!

[@BigDog50001]

I appreciate the comment, thanks!

[@reviewittv1802]

A thought, Honda has put out a longer tensioner pully bolt for the timing belt because the original was not long enough and was stripping possibly causing new time jobs to come out of timing because the pully allowed the belt to loosen immediately and skip teeth causing the Map p1129 code to pop up right after a timing job was done. Just a thought if the timing was done and then you immediately had a Map senor causing engine light and you have confirmed the sensor and harness are good with a meter.

[@BigDog50001]

If that happens, the tensioner bolt will still be loose (it won't tighten itself back up), which should be a clue to what caused the belt to jump teeth.

[@reviewittv1802]

The reason I say Honda says the original bolt is not long enough is I neglected to mention that it has to do with these aftermarket tension pulleys not the OEM pulley that most people use when they replace it. Alot of these aftermarket pulleys are slightly wider then the original OEM pulley and the oringinal bolts weren't long enough so honda put out a longer bolt but most people havent discovered this particular issue if they use OEM parts. Alot of these aftermarket pulleys dont come with a new bolt. I just went through this with my daughter's 03 Honda Civic EX after just doing the timing within 1 day the timing skipped 2 teeth and P1129 came on, before discovering it just skipped 2 teeth I figured there was no way P1129 was from the timing that we had just done so replaced the Map sensor and light came back on again so I found your video which led me to relook at the timing finding skipped teeth resulting from tensioner pulley bolt issue. I am only speculating on what i found after having P1129 pop up from just setting the timing right to not having P1129 at all prior to car dying from being out of time to begin with. I replaced bolt and adjusted timing again and now no engine light/ P1129. Nevertheless great video and it indeed helped me to stop chasing new parts. Thanks.

[@Allbbrz]

i didn't catch how the actual repair was done.... just the idler bolt ???

[@20SkyWatcher09]

Awesome info and vid. Throwing parts now😂

[@zephyrandboreas]

Thank you. Very informative and I loved that you made diagrams and explained everything in detail. I found your channel because I do have a engine light on and a P1129 on my Honda CRV. Car starts, runs OK for some 15-20min, then suddenly loses power, shakes and revving does not help. And afterwards the engine start is quite rough. It happens irregularly and at the dealership they claim not having been able to reproduce the 'symptoms'. So, this video gives me information to discuss rationally with the mechanics. I am not educated in car mechanics and invested some money on a not expensive OBD2 reader (I did not even know those things existed). Hope it helps. Big thumbs up to you!!!

[@seaton95]

thanks for video you explanation is clear an understandable one question .what is different between ect1 and ect2?

[@BigDog50001]

Both are coolant temp sensors but they are in different locations. On Hondas one is usually near thermostat and one is usually near the bottom of radiator. The engine computer uses both to monitor the cooling system. You can see me talking about them here in this older video of mine. kzbin.info/www/bejne/gGfddKmZg5WkgNk

[@johngraham2470]

I recently called My Mechanic app people to change Tensioner pulley and serpentine belt on my 2013 honda civic. Some noise started coming since he changed the tensioner and belt. After one month of driving P1129 code triggered. Is It because of bad fitting of tensioner? Because he struggled for 3 hours to fix it. I doubted if is expert or learner. Does bad fixing of Tensioner effect timing? My tensioner and Belt are OEM from Honda.

[@validatedcustomer604]

great video. unfortunately I've already fired the parts cannon, yet my 01 accord has this, I believe to be an intermittent electrical issue, because my temperature sensor keeps going out (temp gauge drops cold), my transmission wont shift out of park ,and wont shift up or down while driving, followed by a p1106. these things happen all together every time. when I park my car and start it again, its all back to normal for a day or two. please help.

[@reedraven7068]

i followed this video and adjusted the cam timing,i reset the ecu after the car runs better but the code went back and my car is having a rich fuel mixture,will the error just go away in time after the ecu adopted to it or do i need to do something else?thanks for this video🙂 hope my car get fixed soon its a civic lxi 1999

[@heyitschinoable]

Wow excellent job and experience! 👏

[@BigDog50001]

Thank you, I appreciate all the comments you make!

[@ibrezwaan]

Thank you very much for this video buddy! My honda civic 98 gave me this error code also and I commited the error of buying parts that it didnt even need. Now i got a mecanic to check my car out and it seems that the water pump is not working, do you think that could be the reason for that map code to pop out?

[@tylerbehrends3304]

Hey so I’m 90% sure this is my problem, I’m getting the p1129 code as well as “intake leak” codes, and even “ idle RPM higher” codes I have the diagnostic tool plugged in while driving to clear the codes if needed. But when the engine light comes on, I’m pretty sure it’s injecting more fuel, which then makes the engine run WORSE at idle So does this confirm that the timing is the issue? thanks !

[@quangle5319]

i found this code is because of stuck open EGR valve . And the code 2279 too , try to check the egr valve first . It took 5 days for finding this . When you see p1129 or p2279

[@BigDog50001]

👍

[@jackjones9460]

So, did you reposition the timing belt or replace it? Which option? Also, did the timing belt adjust fix the over pressure problem? Could a bad fuel injector also have caused it? Or a cylinder not firing? What made you suspect the timing belt had jumped time? Thank you because I do want to know.

[@BigDog50001]

A new timing belt and tensioner fixed this one. MAP pressure actually being to high (and pulsing) as apposed to being a bad sensor was the clue. Timing off or excessive exhaust back pressure (plugged exhaust) are where I start when I see this.

[@nogamessheep2046]

My 04 ex civic is in limp mode. Can't get any codes back from a scan tool. What should I do next? Thanks.

[@themechanic6117]

That's a nice sticker ! 😂👍 great work. I can only imagine the parts that would have been shot at that car. Btw I finally bought a power probe 3 today! Pretty excited about it lol

[@BigDog50001]

The mech a nic Thanks! That PP should make a nice addition to your tool collection.

[@joelaplnski5394]

Would have a vacuum gage told us about timing issue, for us who don’t have some of those tools? Nice vid, thanks

[@BigDog50001]

A vacuum gauge would have showed that there was a little bit less vacuum than there should have been (which is basically what MAP sensor voltage was also saying). To see timing on these Hondas there are a couple options, you could use a scope to see cam/crank signals, or you could take it apart like it was in video and visually verify timing marks. You can use a 5 cent T Pin and a cheap voltmeter to back probe MAP signal and see MAP voltage changes.

[@cokermaseryer]

Please explain further...

[@geologic740]

Great diagnostics. Thanks for all the good info.

[@BigDog50001]

Thank you, I appreciate the comment.

[@greyhairedmountainbiker116]

Wish I had seen this before buying a Cat!! At least I can tell myself that the timing issue blew the cat. Lol. Weird thing is my car runs and idles ok but no power. EXACTLY the same......2 teeth off

[@BigDog50001]

Thanks for the input!

[@bernardaflores1720]

Could you have been able to see the humps if you where using a normal voltmeter and not a scope???

[@BigDog50001]

Typically no, a voltmeter is not fast enough.

[@bernardaflores1720]

@@BigDog50001Thanks for the info

[@5thsNGunz]

Thanks I been stumped for months

[@BigDog50001]

Thanks for the comment!

[@fukutubeagain]

This video was awesome sir. I am currently trying to chase down a P0172 code on a 2005 Civic LX 1.7L, and I am at a complete loss. It nearly stalls in reverse, idles poorly, hesitates to accelerate. I broke my timing belt, mechanic serviced it, replacing some valves, and machining the head. He couldn't figure out what the issue was with the car after that. I found a broken pcv hose, and a cracked bypass cap (just above pcv). I am not a mechanic, but am tempted to take everything apart, and put it back together again. I have seen enough videos, to want to attempt it. I have cleaned my EGR valve, and replaced gasket, replaced vapor canister purge solenoid. Would you have any suggestions so I can stop throwing parts into it? Thanks in advance if you have time to reply.

[@BigDog50001]

If this happened right after a new timing belt was installed, the work on the new timing belt should be checked again in my opinion. A P0172 can set if the timing is off (usually this happens right after replacing a timing belt/tensioner/water pump etc.). Timing belt not installed or tensioned properly could be the reason. A faulty reporting air/fuel ratio sensor (oxygen sensor) can also cause a rich code and poor running but so can quite a few other things. Thanks for the comment!

[@faustovillanueva3527]

Awesome Thank you

[@BigDog50001]

You bet 👍!

[@jeffersonmartinez883]

Thank you for the interesting video

[@BigDog50001]

👍

[@righteous1229]

Helpful video thanks!!!

[@nso3803]

Super job sir. My reapect to top mechanic you are. 1000 likes and shares for you .

[@BigDog50001]

Thanks 👍!

[@arthurfricchione8119]

great video Big Dog. like the way you use the white board to give out info on what you should be seeing. most other channels don't don't give you that info. very informative explaining the system. really enjoy your Honda videos in fact all your videos because the info you put out can be used in many different ways. Thank You. 👍

[@BigDog50001]

Thank you!!

[@greyhairedmountainbiker116]

Great video! I have a similar situation. Thought it was cat by o2 sensor behavior. Didn't have a vacuum gage.How do you know when you're in limp mode? Also, my Autozone scanner reads in hg pressure not volts. Can you convert? Thanks!

[@BigDog50001]

Oh you will know if it is in limp mode, it will seem like the car is tied to something heavy and can't pull it no matter how much gas you give it. As far as converting, I am sure it can be done but I have not tried to because I can see both readings on many of these Hondas with the scan tools I have.

[@greyhairedmountainbiker116]

Yeah my truck goes into limp mode and you know it. Just wasn't sure on the 4cyl. It will go 50 mph but has a definite power problem and intermittent stalling at stop signs. I guess its not in limp mode . Probably slipped one tooth. I'm getting high MAP (near 30 at load) and negative fuel trim. MAP is around 9 to 11 at idle. Weird thing is it actually runs and idles but only sometimes idle drops real low. Thanks for your input. Happy Thanksgiving!

[@jackdaniels2657]

My car is on time bit i wonder if a bent camshaft wpuld cause this problem

[@BigDog50001]

I like to look for a direction to look towards when I diagnose. Some things I would look at to move in one direction or another would be MAP voltages and Freeze Frame data on a scan tool (among other data) and I would also look at how the vehicle is running. The vehicle in this video was running very very poorly to the point it wanted to stall.

[@jackdaniels2657]

@@BigDog50001 i found the problem i did a valve adjustment. I guess the valve was too tight preventing the valve from fully closing

[@melindadollarhide8603]

I have a 2001 Honda Civic an it still runs but runs like crap.i had maps code an cam sensor code an o2 code. I changed the cam sensor an map sensor an it didn't help it.i then changed the o2 an still no help.think it might of jumped time.but it still runs.

[@melindadollarhide8603]

I'm going to check the timing an see if it's off.thanks for the info

[@jarana10]

Did you ever fixed the problem ?

[@arthurfricchione8119]

Big Dog what model scanner were you using. I see it was an Autel Maxi just wondering what version. was it a 708 or newer version. just shopping around Thanks

[@BigDog50001]

Autel Maxisys MS 906.

[@jackdaniels2657]

Buy the maxysys elite by autel. U can reflash computers and a whole bunch of other shit. But buy it from amazon cus if u buy off the tool truck its 4 grand but if u get it from amazon its like 3 grand and comes with oscilla scope. On the truck u had to pay 500 additional for the oscilla scope

[@ronkrzyzewski8072]

Great video!

[@guillermososa9816]

Got code P1129 on my 2010 Civic ex. Any tips on how to go about finding the problem?

[@BigDog50001]

P1129 is a higher than expected voltage issue with the Manifold Absolute Pressure (MAP) sensor. I would start by looking at what the MAP sensor voltage is, either with a scanner, multimeter or scope (GRN/RED wire at MAP sensor). On a warm engine (above 160 degrees) the MAP voltage should generally be below 1 volt. 1.1 volts or more on MAP sensor on a warmed up engine will generally set a check engine light. If it is 1.1 volts or a little bit above that, there is a good chance it is not a bad MAP sensor and will need troubleshooting as to why the voltage is higher than it should be (vacuum leaks, back pressure from exhaust, timing off etc.). If the voltage is 5 volts then I would look towards broken wires going to the MAP, bad connections at MAP, or a bad MAP sensor.

[@Borkowski.R]

2009 Honda Accord with MAP error code P1129, rough idle and limp mode (won't go past 3,000 rpm). The solution in my case was engine valves adjustment (intake and exhaust valves). Things I have done to the car that failed to solve the above issue, replaced engine oil, new timing chain, replaced VTEC Solenoid module, replaced Variable Valve Timing solenoid, replaced PCV, cleaned throttle body, checked for vacuum leaks.

[@johngraham2470]

@@BigDog50001 My 2013 Honda civic showing P1129, 83-11 and 61-11 any thoughts?

[@martinberlanga4914]

Got the same code on my 2002 Honda Civic ex as well as a p1505 code and tips on tracking down what the problems could be?

[@BigDog50001]

Most likely the P1129 is a symptom, I would go after the P1505 first. The engine does not like the amount of air going in and thinks there is a vacuum leak somewhere in system (most likely PCV system). I would look for vacuum leaks near PCV valve/hose, EVAP purge valve/lines, brake booster, throttle body and any other vacuum lines. Cracks in hoses or hoses disconnected can set this code.

[@martinberlanga4914]

Big Dog50001 Automotive I have tried using a smoke machine to to find a leak but can't seem to find any what so ever I've also disconnected almost every single hose and all check out

[@martinberlanga4914]

Big Dog50001 Automotive Also checked the pcv valve and is good also

[@BigDog50001]

Martin Berlanga Look at MAP voltage and see if it is above/below 1V at idle when warm like I talked about in video. If above 1V and it looks like it is reporting properly, then I would start pinching vacuum hoses and see if one of them causes MAP to drop to normal voltage at idle. If voltage is normal after warm up then it could be a gasket that is sealed when warm and will only leak on a cold engine (smoke test cold to find).

[@martinberlanga4914]

Big Dog50001 Automotive Thanks I'll try that and at idle the map is reading around 3 volts

[@tech3437]

Thank you for the video and just give me some feedback I appreciate you man thanks

[@BigDog50001]

👍

[@erniecarrasco9107]

I didn't clip the air filter cover back on correctly 🤣

[@jackdaniels2657]

I still got the issue.

[@raquelvasquez465]

I've taken my car in this week with a code for the MAP sensor but the repair shop can't figure out why. I originally took my car in because my car was jerking as I accelerated fast on the freeway. Any ideas of what could be going on?

[@BigDog50001]

Anything I say would just be a guess, it needs some diagnostics done. I would start by looking at the MAP signal (on a scan tool and also on a scope) if there was a code for it.