Flashing Check Engine Light

Discussion in 'Wheels, Wings, Mud, and Water' started by Bassblaster, Jan 29, 2018.

  1. spicer

    spicer Well-Known Member

    Messages:
    998
    At the risk of only adding confusion and not being there, I don't know what else to say. I have seen ECMs have problems which included not self reading codes on the light. Try a code reader, if that doesn't work, check all the fuses, if they are all good try to borrow a scan tool.. if not available, you might take it and pay for a diagnosis, and maybe, a repair. Post what you find.. fixes are always interesting.
     

     

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  2. petehall347

    petehall347 the brandy coffee man Subscriber

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    you may need to press the brake or something else whilst turning ign on/off . i just plug the scanner in . unless its a service check warning then its hold a button turn ign on sort of thing .
     
  3. 2011etec

    2011etec Super Member

    On my 2003 4.6 f150 4x4 I installed a cold air system.So motor started running bad and super gutless .There was a large crack in the air duct just before the mass air sensor.Missing air filter,clogged air filter or large crack or damage can all cause issues.
     
  4. Wildcat

    Wildcat Audio Sommelier

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    Many auto parts stores will read your error codes for free--I would go that route for now.
     
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  5. spicer

    spicer Well-Known Member

    Messages:
    998
    Yes.. .that is true, an air leak before the throttle and after the sensor if it uses a mass air sensor... or a faulty manifold pressure sensor, I think that's what you have.. map... can cause the flashing light too.. not for the MAP code itself, if it completely fails or produces an improbable output the ECM will substitute a value and set the engine light on... but if the map sensor becomes unreliable and varies enough to cause engine misfire but not call for a default limp in value, it might cause misfire and the lamp to flash. This is what makes a scan tool showing the data stream so useful. Check the vacuum line to it.
     
  6. bigstereo

    bigstereo Super Member

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    Personally, I consider my scan tool to be just about the most useful tool in my box. That and internet access will allow you to solve a lot of problems by yourself. Worth every dollar that it cost me and has helped me to diagnose problems on my own and others vehicles. Saves you money from just throwing parts at a problem till you finally get it right.
    Even for a vehicle that might happen to still be under warranty at the least you will have a clue when you take it in to the dealer and they will be less liable to give you the runaround. I am far from being "a mechanic" and I know just enough to be dangerous with tools.:idea::dunno::D
     

     

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  7. Wildcat

    Wildcat Audio Sommelier

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    :thumbsup:

    I currently use one of those cheap ELM-327 devices that hooks up via Bluetooth to my phone, and utilize a free app to read the codes.

    I am, however, looking into getting a proper scanner such as an Innova that can also read and reset ABS and SRS error codes, as well as reset oil/maintenance minder codes and perform battery initialization. BlueDriver is an OBD-II dongle that connects to a smartphone or tablet, and seems to be adding support for more vehicles regularly (it can read all OBD-II codes, but features like ABS and SRS are rolling out slowly to different makes and models, and there is no support yet for resetting oil/maintenance codes or battery initialization).
     
  8. Bassblaster

    Bassblaster Super Member

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    So i just got back from O'Reilly's since they do free code readings. what he got was.....cylinder 4,5,6 and 8 misfire. bank 1 #2 O2 sensor shorted and rear and front left ABS sensors bad. Okay, looks like i got some work ahead of me. i figure just replace all plug wires, cap, rotor and coil and that should solve the misfire issue. maybe help the gas mileage. i only get about 7MPG. my RAM 1500 with the 5.9 360 got more than that.
     
    Last edited: Jan 30, 2018
  9. petehall347

    petehall347 the brandy coffee man Subscriber

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    hope the lamda sensor comes out ok . you can test it by reading the voltage as you heat it up .
     
  10. spicer

    spicer Well-Known Member

    Messages:
    998
    That's where I would start, especially since it might be time anyway, then I'd clear the codes.... disconnect the battery for five or so minutes... then start, test drive, and see if any codes return and go from there. The shorted O2 sensor is curious.. read the exact definition for it online.. is it the sensor output shorted (to ground or battery voltage) or is it the heater circuit, which usually means the sensor itself. The code definition should inform you. Inspect O2 sensor wiring, make sure it isn't against hot exhaust somewhere... that's not uncommon. By the way... a shorted primary, before the cat, O2 sensor signal will force the ECM to a rich condition by default which will explain the poor gas mileage.
     
    Last edited: Jan 30, 2018
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  11. Wildcat

    Wildcat Audio Sommelier

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    +1 on this.

    Codes read from OBD-II aren't necessarily the sensor, as @spicer points out. All it means is that there is a fault somewhere in the circuit beyond the computer. It often is a sensor, but can also be any of the wiring up to and including the sensor. The computer expects a value within a certain range and if that is out of range, that is when it throws an error code. Sensors can be tested to a limited extent. What I usually do for a given make and model is check online with the error code--if there is a really common failure item (such as a sensor) for that particular code, I can pretty much guess what might be wrong with the car I'm working on, and go straight to the problem part and test it right away. If the sensor is cheap enough, I often will buy one and throw it on anyway.
     
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  12. gadget73

    gadget73 junk junkie Subscriber

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    I'd fix the misfire first and see if the O2 code goes. Usually the actual code is something about the sensor not switching, which will happen when you have a lot of unburned fuel dumping such as from a bad misfire. The specific code number would help here. They don't always mean what you think they mean.
     
  13. dosmalo

    dosmalo T-Totaled Subscriber

    Glad you're starting to get it sorted out.
    I suggest to stay away from Bosch 02 sensors also. Try to go with NTK (NGK) for your Mopar.
     
  14. Wildcat

    Wildcat Audio Sommelier

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    Agreed here. Bosch is crap. Their sensors are known not to work correctly in some vehicles--new sensors still cause codes to display. I had one of their spark plugs shatter inside the engine and ruin it. I wouldn't even recommend them to someone I hated. NTK/NGK and Denso are good. Denso is original equipment on many cars today.
     
  15. Bassblaster

    Bassblaster Super Member

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    2,051
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    Cambridge, Ohio
    Okay so an update. i replaced all 8 plugs a few weeks back. today i got all the wires replaced, but for the life of me a cant get the cap off. its completely rusted solid and i also can get the screw to move at all. im afraid the screw is gonna snap then ill have to replace the entire distributor. the O2 sensor is completely rusted as well, cant get it out. its wires look good tho. after all that i tried to move it back into the driveway. full throttle it wouldn't even spin tires on gravel. so im going to say the trans is probably about to explode as well.

    i also dont think i would use Bosch secors, too many mixed opinions about them
     
  16. dosmalo

    dosmalo T-Totaled Subscriber

    Soak around the old sensor with some PB Blaster or Liquid Wrench and let sit overnight or so that may help loosen it up to change it out. And be sure you only have the one, my 99 3.5L has 4 of the damn things but the code(s) should tell which one(s) are to blame.
    The deal with Bosch and Mopars is the Bosch 02 sensor does not send the correct heater voltage to the sensor so it'll not only throw another code continuously, it probably will give you driveability probs as well. Either go with the NTK or OEM for the sensor and if you do use PB or Liquid Wrench to bust it loose from the exhaust be sure to clean up well after it comes out so that doesn't foul out your new sensor.
     

     

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  17. Wildcat

    Wildcat Audio Sommelier

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    And buy an O2 sensor wrench if you attempt to change a sensor! Even if it's several bucks, it makes the process really easy. This is the one I grabbed from Amazon back when it was on sale: https://smile.amazon.com/gp/product/B00GMN4D1Q
     
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  18. bigstereo

    bigstereo Super Member

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    4,211
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    As others have already noted, PB the heck out that fitting and give it time to work. I would like to add that some heat applied to threaded area with a torch has saved my rear-end quite a few times in trying to break loose stubborn bolts, fittings etc. I prefer MAPP because it burns a little hotter than propane. So PB, soak, heat up that O2 sensor bung in the pipe and it should break free for you
    PB and a torch are your friends.
     
  19. gadget73

    gadget73 junk junkie Subscriber

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    Location:
    Southern NJ
    Many OEM sensors are Bosch. Interesting the suggestions to stay away from them. I always go for Bosch because thats what the original Ford items were. If Cheesler used Nippon-Denso sensors originally, use those for the replacement. Basically if you replace it with the same type item the factory used, its very likely to work right.
     
  20. petehall347

    petehall347 the brandy coffee man Subscriber

    Messages:
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    Location:
    uk.. the middle bit
    fix the misfires first .not sure on firing order but they seem pretty much one after another so dizzy cap might be the cause .
    could also be a bad set of plugs .once had 3 out of 8 bad . bosch rubbish . put ngk back in and fine then .
    you can test if sensor heater is likely ok with ohm meter . it will be no use if open circuit . you could monitor voltage engine running but wont be correct with all that misfiring . its probably full of soot by now .
     

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