fixed my sister's Yukon yesterday...

[Pete M]

check engine light was flashing, traction control light kept coming on, it was running rough and had hard shifts.  one of the codes said "misfire cylinder 1" and so I pulled the plug and found it all fouled up with baked on oil.  I replaced the plug and now all is well.  that's right, I fixed the traction control and trans shifts by changing a spark plug.    I'm starting to think that the warning was a fake to scare owners into paying attention to the check engine light.  I cannot figure out how all these things can be connected.  any ideas? 

[Minuit]

I've had a really poorly running engine make the transmission feel bad too. Way back when my 91 plugged its catalytic converter it almost felt like the trans was going too. When I got it back from the exhaust shop the first thing I noticed was how much better the trans shifted now that the engine was making full power again. No idea on the traction control 

[HOrnbrod]

On the wife's JKU, she had Low Tire Pressure and Traction Control warnings. I purchased a new tire gauge as my original was over 25 years old, inflated all the tires including the spare to 35psi, and both warning lamps went out in the first mile of driving.  

[Keyav8r]

Little different scenario on my wife’s Mazda6.  Traction and ABS lights went on and off for a while then just stayed on.  Tried airing all the tires up with no success.  Checked Youtube and found a video on cleaning the sensors at each wheel.  Pulled the sensors out and , sure enough, they were all crudded up.  Wiped them clean, blew off the “trigger” wheels or tone rings or whatever through the sensor holes, put the sensors back in, and all the lights went off.

Youtube may not have been invented for us gearheads but it works pretty darn good!

[schardein]

On 2/13/2018 at 6:48 PM, Pete M said:

check engine light was flashing, traction control light kept coming on, it was running rough and had hard shifts.  one of the codes said "misfire cylinder 1" and so I pulled the plug and found it all fouled up with baked on oil.  I replaced the plug and now all is well.  that's right, I fixed the traction control and trans shifts by changing a spark plug.    I'm starting to think that the warning was a fake to scare owners into paying attention to the check engine light.  I cannot figure out how all these things can be connected.  any ideas? 

I was working on my CJ7 with swapped in 5.3 the other day... doing multiple things at once... disconnected the #1 spark plug wire... did some other things... and then started it.  Wouldn't rev, thought I had left the throttle control module disconnected (I had been messing with it too)(it has the electronic throttle pedal).  Push the gas pedal, nothing.  Then realized I had left the spark plug wire off.  Plugged back in and all was well.  Trouble codes indicated the electronic throttle module though... weird.

[DirtyComanche]

A GM flashing the check engine light means there is a severe misfire, and it will then disable other systems as part of its efforts to get you to stop driving the vehicle.

[schardein]

5 hours ago, DirtyComanche said:

A GM flashing the check engine light means there is a severe misfire, and it will then disable other systems as part of its efforts to get you to stop driving the vehicle.

Good to know.

[mjeff87]

And a Chryco/DCA vehicle will flash the CEL to indicate something pretty serious is occurring (or not occurring) and you'd better stop driving it pretty ASAP.  I think in reality any fault that relates to a repeated or multi-misfire will blink the CEL to indicate possible cat converter damage from raw fuel entering it.

 

The 2 times the CEL blinked on my KJ, I really couldn't stop driving it....both were on the interstate in heavy traffic.  One was a #6 misfire due to a leaking coolant hose right above the plug, the other was a #1 misfire due to a shorted coil pack.  Both times I drove it for several miles until I could diagnose and repair.....both were obvious misfires, you could tell by feel.  The strange thing though with the #1 misfire is that I couldn't push the pedal more than 1/2 way or else the whole damn engine started misfiring and it felt like it was going to bounce right out of the engine bay.  Light throttle/part throttle was ok other than the obvious single misfire, but anything over that was a no-go.  Lotsa fun in interstate traffic doing 45 mph, LOL.  My guess is that the #1 plug sets the timing sequence of the whole system and if it's messed up it can affect all the other firing times.  Or something like that.

[Tj1]

I've seen the cel flash on a GM veggie but it was a crank sensor issue with a 6.0

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[gogmorgo]

I drove all the way to California and back with my Jimmy's CEL spazzing at me pretty well constantly. 5000 miles. When I got back I pulled a later real injector spider on 50% off day at Edmonton Pnp ($30!) and put in in place of my poppet spider and suddenly all the misfires went away without needing to do 90mph to use up all the extra fuel. Runs great now. Good times. 

[TheDude]

check engine light was flashing, traction control light kept coming on, it was running rough and had hard shifts.  one of the codes said "misfire cylinder 1" and so I pulled the plug and found it all fouled up with baked on oil.  I replaced the plug and now all is well.  that's right, I fixed the traction control and trans shifts by changing a spark plug.    I'm starting to think that the warning was a fake to scare owners into paying attention to the check engine light.  I cannot figure out how all these things can be connected.  any ideas? 

 

Almost all modern cars will shut off traction control and abs if the check engine light is thrown just in case it could interfere with there operation.

A flashing check engine is universal for all makes as a severe misfire.

 

 

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