Honda CRV P0171 P0174 Brake Fail Causing Engine Problems

47 thoughts on “Honda CRV P0171 P0174 Brake Fail Causing Engine Problems”

1. Great vid. Is this the case for a 2012 CRV. I replaced the MAF sensor & O2 Sensor B1/S1. Still have a CEL on.

2. Sad to see you back off. I am an electronics guy, and watching you is like a mechanical apprentice training course. You should package up your videos into a dvd training package for students.

3. 🙂‼️👍‼️🤟‼️

4. Ray, you have a great channel and I have been able to learn some interesting tips and techniques even though I am in my 70's. You have confirmed that there are still some real mechanics out there who care about their customers.

5. My brake booster has a vacuum leak. My fuel economy dropped from 24mpg to 18.5mpg according to the carputer, and I only have about half of my brake assist. Nissan decided to cram the sumgun way up under the windshield cowling, so it's gonna be a bear to replace!

   Now that I think about it, I have a power steering leak too, no steering sauce = no steering assist. Hm. I'm driving a 2004 car from the 80s. Power windows, no power driver assists. 🤣🤣🤣🤣

6. Ray's point is that MAF equipped vehicles – you have to look at everything that can see engine vacuum. Any unmetered air (intake gaskets, TB gaskets, hoses, oil filler cap, oil filler neck, valve cover, PCV hoses, vacuum lines, EVAP valves, and brake boosters) can throw off the system. Even a leaky valve cover can contribute to the problem (crankcase venting out)

   No parts cannon – but thorough diagnostics to trace down faults to zero in on the problem

7. Reeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

8. Sort of the same thing (not really), this reminded me of the CFI Ford Tempo. They would stall on take off after a stop. Fix was,,,,,,adjust the rear brakes. They ran lean and the booster would cause an extreme lean condition when the pedal was released, especially if the throttle was opened quick. Adjusting the rear brakes reduced pwdal travel and problem solved. Hard part was explaining to the customer what the fault was, lol.

9. My dad had a brake servo (thats what we call them in the UK) fail on his old Austin Maxi in the 1970's. This was before computer controlled engine, so no fault code. But the effect of the extra air was to increase the engine speed. So he was slowing for a red light, hit the brakes and the engine started to speed up (car was an auto). He got a hell of a fright and he had to finish the journey using the hand brake.

10. I have a 2007 Dodge Ram 1500 with the 4.7l Magnum that started misfiring out of nowhere yesterday. Got it home and plugged the code reader in, and it gave me the P0171 code, Fuel Trim Lean. I looked and listened all over for a vacuum leak, didn't find anything and since the misfiring only lasted a couple minutes out of a 30 minute drive, I thought maybe it was a glitch in the Matrix. Drove it to the bank and gas station, then came home and parked it for the night. Got up this morning to go to work, and no start. Cranks fine, but it's not firing at all. I got out whacked the gas tank a few times with a plastic deadblow and it fired right up. Dead fuel pump with almost no warning.

    Long story short, if you get a P0171 code and your car suddenly refuses to start, a good place to begin is at the fuel pump.

11. Man! No wife unit?!?!? Come on! She is the life of the videos!

12. Good job Dave.

13. Dave and the smoke machine to the rescue 👍

14. Thank you for the lesson. I never would have thought of that. If someone told me my brake booster was the cause, I would have thought they were lying.

15. Happens all the time up here in western Pennsylvania. Rust issues here are outrageous. Why can someone come up with all the high tech BS new vehicles and EV's have but it's impossible to keep metal from rusting ?

16. You are excellent at explaining how you arrive at your diagnosis! If I ever live near you I will have you work on my car for everything! Keep up the great work!

17. I'd give you two thumbs if the I could.

18. Well done dave 👌😎

19. Great analysis of a complex problem.

20. Rebuilt a few of them in my time I’m old school was taught how to rebuild a lot of things instead of just replacing them

21. Way to go Dave !

22. Here is a comment, for the algorithm.

23. I love it when you Smoke My Mind!

24. Can one test the brake booster with a hand-held vacuum pump, to see if it holds vacuum???

25. MAP sensors, more reliable than MAF sensors.

26. Nice

27. I just finished a mercedes that had a ton of codes,ecm internal fail,fuel trim,all kinds of crazy stuff! Bad Wheel bearing!!!!!

28. 🎉Will that booster leak make the brake pedal feel mushy?

29. I'm convinced You are a Doctor, great diagnostic skills 🙏

30. I'm old school enough I've never worked on a engine with any electronics at all. Electromechanical was the thing, if even that. So no codes to guess about. Either the thing ran or it didn't, and if it ran decently that was often good enough. I have to say it's inspiring to see that the darned electronical hogwash actually helps technicians to get things working, and it even improves on "good enough" standards. Last I looked even slightly at one it was all brand specific. You needed a computer from the car brand and those were only sold to licensed technicians and only at ridiculous prices.

    When I was a kid there was a neighbor who worked on some French car brand in his garage. They sent him the really sick cars that the brand garages had missed fixing at least three times, and he would diagnose and most of the time have it fixed in a couple of days. Those he couldn't repair were basically ready for the scrapyard. This was before the computer was considered cheap and reliable enough to use in ordinary cars. So it was all experience and being stubborn enough to actually find all the weird problems only by hand and feel. I know technicians still has this ability, but modern cars are more advanced, has a lot of tech added that no one had thought of back then. Things such as catalysators or the fuel tank evap that keeps gasses from the tank in check. So having a computer tell you all these details really helps.

31. Finally, a video less than 30 minutes long (or 1 hour.. or… whatever it was these days…)

32. Ray, the length of your videos is getting out of control!! I grew a beard watching this one!

33. Been having the same codes in my 4th-Gen TL. It’s been driving my crazy for months.

34. Proof positive that you must test the entire system. Good catch by you and Dave.

35. You’re a generous!!

36. Usually there's a check valve on the booster and they have been known to fail.They are used so you have at least ONE assisted stop if the engine dies,after that you will be pushing a lot harder on the pedal to stop-so plan ahead

37. I have used my smoke machine many times and have never even thought of using it on a brake booster. Good job and thank you

38. Dave’s diag for the win👍👍nice work fella.
    ( Reckon he’s a keeper Ray👍👍)

39. Way to go Dave 👍👏👍👏

40. Good info to know! Never would have guessed the leak was in there !! Keep up the good videos

41. Why did it have to be removed to smoke test ?

42. This is the first time I've seen 549,000 subs. I'm spreading word, working to reach 550.

43. Always wise give the MAF sensor a rinse for good measure

44. The old fashioned way to check that is by clamping off the hose to the booster with pinching jaws vice grip with the engine running. You can also pull the hose off at the booster and block off the hose with your thumb. Often you can smell the burning brake fluid in the exhaust.

45. Dave for the win! 👍👏💯

46. Way to go Dave

47. Your right I would never guess brake booster cause lean code, but your wrong about one thing, the proof wasn't in the pudding, it was in the smoke, Reeeeeeeeeeee……..

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