Usually when a cat goes bad it's because something killed it. I then explained to the service writer, since I've worked as a mechanic, that I've never heard a new or rebuilt engine knock unless there was a mistake made or a faulty part installed. Can't believe how nicely it runs for 210K miles Oops. Catalyst System Efficiency Below Threshold Bank 1 Now searching this online it seems no to be very serious. This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation.
That appeared to be the problem right there so off to the parts store for a new set of lower intake manifold gaskets. Let me know, if needed further assistance. Has anyone else had this problem? I am going to remove the valve , clean and replace gasgets first before doing the 100 bucks deal. P0505 - High Idle After repair I noticed the idle seemed a little high in some situations, it took a long time to drop down to low idle when coming to a stop, at low speeds you had to fight the engine a little on the brakes and coasting down hills it really picked up speed quickly. I think ther is a gm bulletin on this.
How does a mechanic diagnose the P0404 code? YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. The idle is a tad rough at times but I don't hear any miss at the tail pipe. Any way to get pictures on your response to be readable. A warm-up cycle occurs when the coolant temperature has risen 22°C 40°F from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C 158°F during the same ignition cycle. The only other thing I have had to do is replace the Fuel Pump in the tank, which of course once that was done now my Gas needle goes back and forth very very very fast whether vehicle is idling or driving, and from what I have read this could be a ground or a problem with the sending unit, seems like as time goes by the replacement parts get more expensive and less reliable.
You may want to make sure you don't have anything else wrong too. At this point I could pretty much rule out ignition problems as the source of the misfire. If so what did you do? About 70-80 percent of the time this is the cause. The connector and wiring is fine from intial inspection. You may find something by removing the egr and cleaning the ports. Detonation can lead to engine damage. Can anyone recommend a logical approach to tackle this? I have checked the wiring and everything seems ok, I will clean the contach on the connector when I have it all apart.
This should be looked at by someone qualified to diagnose straight away. The origional problem was a broken valve spring that was throwing raw fuel out the exhaust and killed the cat. There are pros and cons to both repairs that you are considering. Thanks, I just saw the other post concerning P0404. The manual wasn't clear about the correct readings of V8 coils but they matched the readings I got off other known working coils.
Test Description The numbers below refer to the step numbers on the diagnostic table. It may be stuck open or shut. I live in an area that doesn't inspect for smog crap. I was wondering if anyone had any luck cleaning these and what the odds are that the code may be caused by another problem or sensor out of tolerance. Truck currently has 38,000 miles.
Thanks for using ' Fixya ' and have a nice day!! My check engine light came on yesterday, when it came on it beeped at me i thought it was serious because i have never had one beep at me before, so i took it to my machanic and he pulled the code for me. Please feel free to leave a comment below if there is anything that you would like to add that can improve this article. So is this a bad sensor, the wiring harness looked ok from what I could tell. They had the code for a few weeks until it clogged all the way up and had to be towed. Now that you mention it, the light did come on the first time after topping a hill and coasting down the other side. When it fails to recirculate this gas it can raise the combustion chamber temperature.
If it is damaged, repairing it should solve the problem. Diagnostic Aids Be sure to check for intermittents. I put new cat's on it and it was fine. Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Have heard of possible links to plugged cat. Our truck's performance has gone down due to the knock sensor detecting this particular problem.
If I swap the cat for a straight pipe and eliminate it, will that kill the cat problem? Should i replace my cat with a high flow? If the light continues to illuminate, then you will know that the will need to be replaced. I have yet to experience any stalling or hesitation. Due to the , you will want to start by replacing the sensor. When I left work yesterday, the service engine light came on and I scanned it , came up with code P0404 again. .
The light has been out for the last three days now with no troubles. The noise is usually more noticeable on the intial start-up when the tempture is below 50 degrees and may be more pronounced on the first start following a long trip. The knock noise is most often noticed during start-up and typically disappears within the first 5-30 seconds may last longer in extreme cold temperatures since we live in alaska this is very true. The pintle was frozen closed with corrosion and carbon but I was able to free it up pretty easily. The second time was coasting toward a turn off on the highway. I cleaned it as best I could and put it all back together but the P0404 code has returned.