3 ms·

My understanding is that such parts are not by themselves illegal. The relevant text regulating the sale and manufacture merely allows the EPA to exempt produc

My understanding is that such parts are not by themselves illegal. The relevant text regulating the sale and manufacture merely allows the EPA to exempt products "that you intend to be used solely for competition, where we determine that such engines/equipment are unlikely to be used contrary to your intent." > but a part of me does not like the idea that every vehicle owner is beholden to the OEM for parts in perpetuity. I don't think the regulation requires OEM parts, Dorman and MagnaFlow sell bolt-on Catalytic converters without any trouble from the EPA. I think there is a real problem when it comes to more complex parts like ECUs but right to repair laws can help solve that by requiring documentation and restricting arbitrary locks of electronic components. https://www.ecfr.gov/current/title-40/chapter-I/subchapter-U/part-1068/subpart-C/section-1068.235 https://www.ecfr.gov/current/title-40/chapter-I/subchapter-U...

Scoundreller 3y ago
I was thinking more about O2 sensors. At least a lot of Toyotas don’t like the aftermarket ones for some reason. No idea if they’re truly out of spec or what. But there’s a risk with living with a check engine light. Some vehicles disable stuff like traction control in that state, and you won’t know when a new unique code has hit that you should deal with for other reasons. (The disabling of traction control is insane to me here: https://mechanics.stackexchange.com/questions/25383/why-does-the-check-engine-code-for-emissions-failure-disable-traction-control-an https://mechanics.stackexchange.com/questions/25383/why-does... ). A catalytic converter problem is zero reason to do this.
- I_Am_Nous 3y ago
  My old Suzuki SX4 (RIP) disabled cruise control when it threw a code, but so far as I could tell that was the only thing it did. Traction control still worked, automatic/manual all wheel drive still worked...it was also a secondary catalytic converter alarm, so I just kept a code reader with me and reset it whenever it would come on. It would always come on after I got off the interstate and coasted up the on-ramp, so I am not sure if it came on after getting hot enough on the interstate or if it was just the coasting that caused it.
  - hunter2_ 3y ago
    > reset it whenever it would come on > It would always come on after I got off the interstate and coasted up the on-ramp, so I am not sure if it came on after getting hot enough on the interstate or if it was just the coasting that caused it. I suspect you may have had a very regular time/distance in the repetitive sequence of [reset code, drive some amount, code comes back]. For low-priority codes (unlike major engine emergencies) the ECU will use a "fault frequency" counter to suppress nuisance check engine lights that don't actually need fixing (like if a sensor was briefly out of range just once, a fluke rather than indicating a problem). So if it increments the fault frequency counter for that particular problem once every 10 miles of the fault actually happening continuously, and doesn't throw a check engine light until it counts to 6, then the light will come on after 60 miles. Just making up numbers but you get the idea... so if you always reset it that much driving before the same on-ramp, then it will always light up at that point. Also, the fault frequency counter might reset with every drive cycle, rather than just at the point that you cleared the code. Taking a detour during the same drive cycle as the on-ramp (as opposed to relying on variance of how long ago you did a reset) would be a good experiment. But if you know that the drive cycles weren't so regular, then it could indeed be related to overrun fuel cut (coasting) or whatever.
    - I_Am_Nous 3y ago
      It would basically always happen after about 30 minutes of interstate traffic at 70 MPH (using Cruise Control), but it generally didn't happen if I was only driving at 55/60 on standard highways. Just one of the quirks of the car :)

Scoundreller 3y ago

I was thinking more about O2 sensors. At least a lot of Toyotas don’t like the aftermarket ones for some reason. No idea if they’re truly out of spec or what. But there’s a risk with living with a check engine light. Some vehicles disable stuff like traction control in that state, and you won’t know when a new unique code has hit that you should deal with for other reasons. (The disabling of traction control is insane to me here: https://mechanics.stackexchange.com/questions/25383/why-does-the-check-engine-code-for-emissions-failure-disable-traction-control-an https://mechanics.stackexchange.com/questions/25383/why-does... ). A catalytic converter problem is zero reason to do this.

I_Am_Nous 3y ago
My old Suzuki SX4 (RIP) disabled cruise control when it threw a code, but so far as I could tell that was the only thing it did. Traction control still worked, automatic/manual all wheel drive still worked...it was also a secondary catalytic converter alarm, so I just kept a code reader with me and reset it whenever it would come on. It would always come on after I got off the interstate and coasted up the on-ramp, so I am not sure if it came on after getting hot enough on the interstate or if it was just the coasting that caused it.
- hunter2_ 3y ago
  > reset it whenever it would come on > It would always come on after I got off the interstate and coasted up the on-ramp, so I am not sure if it came on after getting hot enough on the interstate or if it was just the coasting that caused it. I suspect you may have had a very regular time/distance in the repetitive sequence of [reset code, drive some amount, code comes back]. For low-priority codes (unlike major engine emergencies) the ECU will use a "fault frequency" counter to suppress nuisance check engine lights that don't actually need fixing (like if a sensor was briefly out of range just once, a fluke rather than indicating a problem). So if it increments the fault frequency counter for that particular problem once every 10 miles of the fault actually happening continuously, and doesn't throw a check engine light until it counts to 6, then the light will come on after 60 miles. Just making up numbers but you get the idea... so if you always reset it that much driving before the same on-ramp, then it will always light up at that point. Also, the fault frequency counter might reset with every drive cycle, rather than just at the point that you cleared the code. Taking a detour during the same drive cycle as the on-ramp (as opposed to relying on variance of how long ago you did a reset) would be a good experiment. But if you know that the drive cycles weren't so regular, then it could indeed be related to overrun fuel cut (coasting) or whatever.
  - I_Am_Nous 3y ago
    It would basically always happen after about 30 minutes of interstate traffic at 70 MPH (using Cruise Control), but it generally didn't happen if I was only driving at 55/60 on standard highways. Just one of the quirks of the car :)