Never heard of this on a 420a. This is usually an issue with Mitsubishi motors, to the point where 96-98 talon tsis (but not eclipses, go figure)are exempt from emissions as per the EPA. I know many people switch their ecus to 98-99 ecus because they are more lax in the readiness demands, but usually throw a cel for emissions beacause the 98-99s had more emission sensors or something to that effect. This is with 4g63s, but perhaps it has something to do with the car being a 99 and you using a 97 ecu. Is the wiring harness from 97 or 99?

Your 420a should not be having this problem. Your ecu is resetting when you turn off the car, there is a problem with the main power source

For reference I submit my 96 gs getting an inspection done here in Texas. This was before I found a set of oem tail lights. Don't judge it had 68k miles and I paid 4k and it was in like new condition. It was done right with ground control coil overs and koni shocks to give an example of its quality

My gst however had to be on the rollers for an active sniffer test this year, the 4g63 displayed not ready until the ecu upgrade that came in late 97 if I recall correctly

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Here are some EPA documents concerning emission & readiness codes. This issue effects both Eagle & Mitsubishi equally. You may have extra troubles trying to get thing resolved though. If I'm reading these correctly, DSM got the non-turbo platform compliant for 1996 & newer.

chrysler kid said:

Your 420a should not be having this problem. Your ecu is resetting when you turn off the car, there is a problem with the main power source

For reference I submit my 96 gs getting an inspection done here in Texas. This was before I found a set of oem tail lights. Don't judge it had 68k miles and I paid 4k and it was in like new condition. It was done right with ground control coil overs and koni shocks to give an example of its quality

My gst however had to be on the rollers for an active sniffer test this year, the 4g63 displayed not ready until the ecu upgrade that came in late 97 if I recall correctly

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Sniffer in TX? That's weird, I thought all you need is no CEL and and monitors to be ready, this is how I passed my Talon. Maybe this is just a Houston thing.

oneslowwdsm said:

Sniffer in TX? That's weird, I thought all you need is no CEL and and monitors to be ready, this is how I passed my Talon. Maybe this is just a Houston thing.

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It depends on the county. County does it by population size. Your car is also a 97, my 96 4g63 reads not ready regardless of how long it is driven. When it reads not ready the computer prompts the inspector to begin drive cycle emissions testing. I was suprised myself as I couldn't recall having to do that before but it's been a few years since my last turbo 2g

PlanZero said:

Never heard of this on a 420a. This is usually an issue with Mitsubishi motors, to the point where 96-98 talon tsis (but not eclipses, go figure)are exempt from emissions as per the EPA. I know many people switch their ecus to 98-99 ecus because they are more lax in the readiness demands, but usually throw a cel for emissions beacause the 98-99s had more emission sensors or something to that effect. This is with 4g63s, but perhaps it has something to do with the car being a 99 and you using a 97 ecu. Is the wiring harness from 97 or 99?

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The wiring harness is from a 99

chrysler kid said:

It depends on the county. County does it by population size. Your car is also a 97, my 96 4g63 reads not ready regardless of how long it is driven. When it reads not ready the computer prompts the inspector to begin drive cycle emissions testing. I was suprised myself as I couldn't recall having to do that before but it's been a few years since my last turbo 2g

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So you think if i can get my hands on a 99 ECU it might be easier to pass me?

Mello said:

Here are some EPA documents concerning emission & readiness codes. This issue effects both Eagle & Mitsubishi equally. You may have extra troubles trying to get thing resolved though. If I'm reading these correctly, DSM got the non-turbo platform compliant for 1996 & newer.

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I have tried taking the appendix j to the inspection site but i think they only ran it as 97 and it still failed in their computer, should i try taking it to a different shop and showing them the appendix-j and hope they only do the sniffer?

I had a very hard time getting my 97 Tsi to pass here in PA because even though the EPA recognizes it as a problem vehicle (as of 2012) the state's software is 10 years old and does not recognize it. I basically had to plead with a guy in Harrisburg to give me a free pass. However, my 96 Tsi passed even though all I/m monitors failed. Once I realized this I proceeded to remove all emissions related components from my vehicle . One more reason talons are better.

Dedge said:

So you think if i can get my hands on a 99 ECU it might be easier to pass me?

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I'm no expert, but between the difference in ecus from 97 and 98+ and the fact that your harness is from a 99, if you can find a 99 ecu for cheap I'd try it.

Dedge said:

So you think if i can get my hands on a 99 ECU it might be easier to pass me?

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No. Like I mentioned my 96 gs with the 420a passed emissions no problems. You have a wiring problem

I just bought a 1997 GST and they are struggling to get it to test out. FIRST they wouldn’t believe me that it needed to go on the dyno for inspection, but after an hour they are finally going to get it on the machine. Struggle is real.

To update ... they can't get the machine to prompt and allow my car to pass on the dyno. Multiple shops had this problem. Not very excited at all.

tunernewb92 said:

To update ... they can't get the machine to prompt and allow my car to pass on the dyno. Multiple shops had this problem. Not very excited at all.

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Pull the black box ECU out of the 99 gst and install it in the 97.

In Texas you can petition the state for exemption and they will arrange for a certified technician to examine and inspect your car. I had a customer with a 97 3000gt vr4 Spyder who had to do this. I believe he had to contact his registration office to find the process.

The 95-96 cars had a different crappy vapor vent system. I believe the charcoal box was moved further back to the gas tank in 97, long story short you should be able to plug a black box 98-99 ECU into a 97 car without problem. The black box ecu's did not suffer from the not ready issues

Again to the original topic, the 2g non turbo 420a cars did not have these problems, the ECU was more capable from the factory than the limped along dsm turbo ECU. If you have a 96-99 eclipse rs or gs your car should pass the OBD2 drive cycle tests. If it does not you are having wiring or ECU issues that are unique to your personal car, not the known "not ready" trigger issues with the turbo models with the 96-97 turbo cars


If you're desperate, Mitsubishi release a technical service bulletin regarding the issue. Technicians can use their programming software to trigger the ready command and then the technician can perform the state inspection. Owners mention that Mitsubishi charges $120 for that process

I did finally get an inspection Yesterday. The problem apparently was in that nobody is maintaining the machines as Texas is phasing them out in 2020. I finally went to a shop that had just gotten their machine fixed last week in addition to being a different brand machine than the rest (according to the state office) and it passed no problems.

I will be going blackbox, but just haven't had much time in the last few days, and with the state trying to be helpful I just wanted to see it pass stock.