Won't Reset for Smog Test; P0125/ 0173/ 0300/ + Cruise Control/ Speed Sensor Error
- Thread starter cr4x4cruiser
- Start date
jeep-N-montero
Expedition Leader
I had to have mine tested at a county inspection station first year I had it, they performed the manual roller test using the sensor in the tailpipe and passed it, they have since updated the testing station computers with the service bulletin and can get it tested anywhere. It was a known and documented issue for the I/M monitors not being "ready" for certain year Mitsu vehicles.
I'm in Michigan so I don't have to deal with what you guys in CA do, although I'm sure I'd pass if I had to. Here is my 2 cents:
1. Since you passed the sniff test you know your cats are working, right? Their job ultimately is to clean up the waste and I'd imagine they engineered them to still be able to do their job even with a few minor engine issues occurring. Meaning the minute you have a CEL for a rich condition, that doesn't mean your cat can't still clean up the problem. I'd say things need to get pretty out of whack overall before your cat's potential is maxed out. I'm running original cats at 225k with no problems. When I rebuilt my engine, I installed new O2 sensors, that's all. I'd say passing sniff test is a very good indicator that your cats have some life left in them. A brand new cat could trigger a CEL if you send more crap at it than it can deal with. If your cat has never been overheated excessively and your engine isn't sending it a load of crap, they last a long long time.
2. As far as the electrical, I'm not sure if all (or any) of the sensors actually operate at 12v, I know some on other cars operate at 6. Your computer takes 12v'ish to operate, but I'd bet some sensors are not operating at 12. What I'm saying is i doubt they would engineer critical sensors to not be able to operate without 12v. Personal experience tells me this is true, as you can limp a car on a dying battery with a failed alternator for a while, well below 12v. Basically I'm saying that I wouldn't blame your alternator if otherwise the car runs "normally". I don't think engine computers are that sensitive to small voltage fluctuations.
Good video on testing a cat:
https://m.youtube.com/watch?v=9VZ5K8n5jj0
1. Since you passed the sniff test you know your cats are working, right? Their job ultimately is to clean up the waste and I'd imagine they engineered them to still be able to do their job even with a few minor engine issues occurring. Meaning the minute you have a CEL for a rich condition, that doesn't mean your cat can't still clean up the problem. I'd say things need to get pretty out of whack overall before your cat's potential is maxed out. I'm running original cats at 225k with no problems. When I rebuilt my engine, I installed new O2 sensors, that's all. I'd say passing sniff test is a very good indicator that your cats have some life left in them. A brand new cat could trigger a CEL if you send more crap at it than it can deal with. If your cat has never been overheated excessively and your engine isn't sending it a load of crap, they last a long long time.
2. As far as the electrical, I'm not sure if all (or any) of the sensors actually operate at 12v, I know some on other cars operate at 6. Your computer takes 12v'ish to operate, but I'd bet some sensors are not operating at 12. What I'm saying is i doubt they would engineer critical sensors to not be able to operate without 12v. Personal experience tells me this is true, as you can limp a car on a dying battery with a failed alternator for a while, well below 12v. Basically I'm saying that I wouldn't blame your alternator if otherwise the car runs "normally". I don't think engine computers are that sensitive to small voltage fluctuations.
Good video on testing a cat:
https://m.youtube.com/watch?v=9VZ5K8n5jj0
Last edited:
cr4x4cruiser
Observer
Final Analysis;
Front Passenger-Side Catalytic Converter was defective.
Replacement - w/ correct C.A.R.B. approved - Catalytic Converter allowed vehicle to pass the smog test with flying colors.
Footnote: The EVAP part of the monitoring/ test may never reset... that is, until you replace the Catalytic Converter.
Good luck to all... if required, I highly recommend the Catalytic Converters from 'Miller'.
Wm.
Front Passenger-Side Catalytic Converter was defective.
Replacement - w/ correct C.A.R.B. approved - Catalytic Converter allowed vehicle to pass the smog test with flying colors.
Footnote: The EVAP part of the monitoring/ test may never reset... that is, until you replace the Catalytic Converter.
Good luck to all... if required, I highly recommend the Catalytic Converters from 'Miller'.
Wm.
cr4x4cruiser
Observer
After several hundred miles [under 111.000 mi] no codes have returned... the CEL has not turned back on.
Then again, for CA emissions, it matters not if the EVAP monitor does not reset.
But, there are no faults with the engine diagnostics / codes.
The truck sounds like a sewing machine... it is actually in better condition than my other ['99 / 115.000 mi] - which is also going in for a timing belt/ water pump/ cam seals [front]/ crankshaft bolt service.
Mitsubishi Service Center: Replace the Catalytic Converter
Mechanic: Replace the Catalytic Converter
Smog Shop: Replace the Catalytic Converter
We - finally - replaced the Catalytic Converter and all is well... some of the best $400 [$200 > C.C. / $200 > Muffler Shop Removal/ Install] we ever spent [really].
Then again, for CA emissions, it matters not if the EVAP monitor does not reset.
But, there are no faults with the engine diagnostics / codes.
The truck sounds like a sewing machine... it is actually in better condition than my other ['99 / 115.000 mi] - which is also going in for a timing belt/ water pump/ cam seals [front]/ crankshaft bolt service.
Mitsubishi Service Center: Replace the Catalytic Converter
Mechanic: Replace the Catalytic Converter
Smog Shop: Replace the Catalytic Converter
We - finally - replaced the Catalytic Converter and all is well... some of the best $400 [$200 > C.C. / $200 > Muffler Shop Removal/ Install] we ever spent [really].