996 SAI Emissions Check
Thread Starter
Racer
Joined: Aug 2001
Posts: 355
Likes: 5
From: Santa Monica, CA
996 SAI Emissions Check
Having just completed an engine rebuild on our 996 (LN Engineering Nickies after buying with a cracked cylinder) the car runs absolutely wonderfully. Couldn't be happier with the result. However, it needs a smog check to take it off NonOp status, and it will not clear the SAI cycle check. Here's what I know:
The air pump works, blows plenty of air from cold start for the right amount of time (about 90-120 seconds).
There is no check engine light
The O2 sensor voltages behave exactly as they should during the cold start SAI cycle as described in other threads here on Rennlist
All other emissions test cycles are ready except for the EVAP one that is not necessary here in California.
I've done three drive cycles all with the same result
Tomorrow I'm going to a guy I know that has a PWIS to see if that might give more clues than I can see but in the meantime....
Any ideas from the collective experience?
The air pump works, blows plenty of air from cold start for the right amount of time (about 90-120 seconds).
There is no check engine light
The O2 sensor voltages behave exactly as they should during the cold start SAI cycle as described in other threads here on Rennlist
All other emissions test cycles are ready except for the EVAP one that is not necessary here in California.
I've done three drive cycles all with the same result
Tomorrow I'm going to a guy I know that has a PWIS to see if that might give more clues than I can see but in the meantime....
Any ideas from the collective experience?
Rennlist Member
Joined: Oct 2010
Posts: 7,773
Likes: 7,062
From: Alabama USA
The PIWIS will "FORCE" the SAI test and set the readiness flag...
The DME actually doesn't do the SAI test when cold , it waits untill the engine is fully warmed up and a lot of conditions are met, then it does the SAI Test at idle at a red-light ...( sorta randomly ..lol )
The DME actually doesn't do the SAI test when cold , it waits untill the engine is fully warmed up and a lot of conditions are met, then it does the SAI Test at idle at a red-light ...( sorta randomly ..lol )
Racer
Joined: Feb 2024
Posts: 391
Likes: 298
From: Khartooshkaville, ID
CA tests to see if SAI works?
Slakker says SAI not really needed and can be eliminated in any of their engine builds. Brandon said leave it off, just plug a few holes and be done with it.
Maybe call Brandon @ Slakker and ask his expertise on what to do? Lucky for me and millions of others, we don't have to put up with CA fanaticism. JMO.
YMMV
Slakker says SAI not really needed and can be eliminated in any of their engine builds. Brandon said leave it off, just plug a few holes and be done with it.
Maybe call Brandon @ Slakker and ask his expertise on what to do? Lucky for me and millions of others, we don't have to put up with CA fanaticism. JMO.
YMMV
Last edited by Siberian14; Jun 8, 2026 at 01:15 PM.
Thread Starter
Racer
Joined: Aug 2001
Posts: 355
Likes: 5
From: Santa Monica, CA
Thanks, guys. Another drive cycle done but not SAI check cleared. EVAP cleared. The guy with the PIWIS says that the "force" has limited success from his experience so I'm going to try another cycle before going that way and taking his time from his autoshop.
Fingers crossed
Fingers crossed
Rennlist Member
Joined: Oct 2010
Posts: 7,773
Likes: 7,062
From: Alabama USA
When you try to force the SAI Test with PIWIS it will tell you if all conditions are met. It will not run the Test if all conditions are not met ....And iirr it will tell you which conditions are not met ...
Rennlist Member
Joined: Dec 2022
Posts: 370
Likes: 333
From: Laguna Beach, CA
Fellow CA owner here... and I had the same issue. What drive cycle did you do exactly? I was having trouble getting SAI ready, and ended up following a very specific set of instructions (something like 20 mins under 45mph and 3000 rpm, then 15+ minutes at highway speed, but _not_ above 60 mph). When I did that specific process the SAI flipped to ready almost immediately. I'll see if I can dig up the specific cycle I followed...
Update: found this in another thread and it jives with my memory of what I did:
Start engine, let idle for approx. 2 min, 10 secs.
Accelerate to 20-30 MPH, Maintain steady speed for approx 3 min, 15 secs.
Accelerate to 40-60 MPH, Maintain steady speed for approx 15 mins.
Decelerate and come to a stop.
Idle in Neutral for 5 mins. (manual trans.)
During the drive cycle, do not exceed 3,000 rpm or 60 mph.
I remember reading elsewhere that it's important this is done on a stone-cold engine (i.e., let it sit overnight and then follow this procedure in the morning)
Update: found this in another thread and it jives with my memory of what I did:
Start engine, let idle for approx. 2 min, 10 secs.
Accelerate to 20-30 MPH, Maintain steady speed for approx 3 min, 15 secs.
Accelerate to 40-60 MPH, Maintain steady speed for approx 15 mins.
Decelerate and come to a stop.
Idle in Neutral for 5 mins. (manual trans.)
During the drive cycle, do not exceed 3,000 rpm or 60 mph.
I remember reading elsewhere that it's important this is done on a stone-cold engine (i.e., let it sit overnight and then follow this procedure in the morning)
Last edited by binaryaudax; Jun 8, 2026 at 07:15 PM.
Trending Topics
Rennlist Member
Joined: Dec 2022
Posts: 370
Likes: 333
From: Laguna Beach, CA
I hear you... I had to be very careful about the time of day I chose to do this, and luckily, I'm close to a toll road with light traffic during the day. But doing only 55mph (a safe margin under 60mph) on a toll road from San Juan to Newport really pissed off a lot of other drivers.
Rennlist Stories
The Best Porsche Posts for Porsche Enthusiasts
Every Era of 911 Owner Explained in One Sentence
Verdad Gallardo
Thinking of Buying a Porsche? Do These 10 Things First
Joe Kucinski
Pixar Pals Turned Into 1-of-1 Porsches!
Michael S. Palmer
Theon Goes Full Carbon Fiber With Stunning New Build
Verdad Gallardo
Genius Porsche-Themed Gifts That'll Make Any Dad or Grad Smile
Joe Kucinski
10 Used Porsches Are Selling for Way Too Cheap
Joe Kucinski
Tuner Is Converting Porsche 911s Into Shooting Brakes
Verdad Gallardo
This Coachbuilt Creation Is A Modern Take on the Legendary Porsche 917
Verdad Gallardo
Is This Convertible Cayenne A Steal, Or A Returnless Investment?
Verdad Gallardo
Thread Starter
Racer
Joined: Aug 2001
Posts: 355
Likes: 5
From: Santa Monica, CA
So no joy today after another careful drive cycle, but something odd comes to mind, and could it possibly be related?
In rebuilding the motor a new coolant temp sensor was installed. The old one worked in that it showed the correct normal temperature on the dash gauge. However the new one does not, barely moving off cold, or the 100 mark. At the same time, my OBD scanner shows the coolant temperature at expected levels, around 185-190 degrees.
I understand that the 4-pin sensor runs two circuits. Could it possibly be that a faulty sensor is not giving the ECU what it needs to run the full set of SAI checks? I realize this is unlikely, but everything else seems perfect yet it just won't pass the SAI check.
In rebuilding the motor a new coolant temp sensor was installed. The old one worked in that it showed the correct normal temperature on the dash gauge. However the new one does not, barely moving off cold, or the 100 mark. At the same time, my OBD scanner shows the coolant temperature at expected levels, around 185-190 degrees.
I understand that the 4-pin sensor runs two circuits. Could it possibly be that a faulty sensor is not giving the ECU what it needs to run the full set of SAI checks? I realize this is unlikely, but everything else seems perfect yet it just won't pass the SAI check.
Rennlist Member
Joined: Jun 2016
Posts: 1,094
Likes: 510
From: Fair Oaks, CA
You might check your engine coolant temp sensor (ECT) and your intake air sensor (IAT), they must be within 11 degrees of each other during cold start up or it will never pass readiness test.
Last edited by JohnCA58; Jun 10, 2026 at 01:50 AM.
Nordschleife Master
Joined: Jan 2018
Posts: 7,447
Likes: 4,909
From: Delaware
U can spend $200 for a laptop and pwis clone and force the test. Then u still have a good diagnostic tool on the shelf? Other then that just keep driving the car. At least u r not trying to trip the emisions on a minivan. 😀
Drifting
Joined: Oct 2009
Posts: 2,217
Likes: 439
From: yoou -tah
In rebuilding the motor a new coolant temp sensor was installed. The old one worked in that it showed the correct normal temperature on the dash gauge. However the new one does not, barely moving off cold, or the 100 mark. At the same time, my OBD scanner shows the coolant temperature at expected levels, around 185-190 degrees.
I understand that the 4-pin sensor runs two circuits. Could it possibly be that a faulty sensor is not giving the ECU what it needs to run the full set of SAI checks? I realize this is unlikely, but everything else seems perfect yet it just won't pass the SAI check.
I understand that the 4-pin sensor runs two circuits. Could it possibly be that a faulty sensor is not giving the ECU what it needs to run the full set of SAI checks? I realize this is unlikely, but everything else seems perfect yet it just won't pass the SAI check.
I replaced my coolant temperature sensor chasing an unrelated problem from yours but it was similarly faulty. It would eventually come up but it was bugging me so I replaced it with an OEM sensor that works just like the old one that I originally replaced before installing the faulty one. Good news is it's very easy to do. I tilted up the passenger side to limit losing the coolant. Really not necessary and there wasn't much. Only just a little, less than an ounce or two. I captured it because I was wondering how much I would need to replace but it wasn't at all significant. Just have the new one ready and get it in place quickly. Some people talk about draining the whole system and what not. Forget that, just unscrew the old one and pop the new one in.
Also, for what it was worth, the original was fine, the faulty one didn't seem to affect anything, and the new OEM unit is now working just like the original.
Last edited by Otto Bonn; Jun 11, 2026 at 02:21 AM.
Advanced
Joined: May 2012
Posts: 60
Likes: 30
From: First Coast
Had to deal with this SAI problem when I was living in SoCal. Funny enough, the day I had an appointment to bring the car to an indy for the PIWIS scan/work, the CEL was gone when I started the car. Before that, I tried doing the "proper" drive cycles, following the steps to a T. No luck. Just kept driving it anyway. Light disappeared by itself after several drives, city and highway.
Long story short, it's just the drive cycles. ECU wants to see all conditions before CEL goes away. Drive it as much as you can and it'll clear itself.
Long story short, it's just the drive cycles. ECU wants to see all conditions before CEL goes away. Drive it as much as you can and it'll clear itself.
Thread Starter
Racer
Joined: Aug 2001
Posts: 355
Likes: 5
From: Santa Monica, CA
Finally! The case cleared the SAI check this morning, and a fresh smog certificate and license tags are now in hand. A new OEM temp sensor made a difference perhaps, but a number of drives finally got it over the line. I was sure the engine was fine, esp having checked the O2 sensor responses, and finally it cleared
thanks all for your contributions, and note I can go run the motor in and enjoy
thanks all for your contributions, and note I can go run the motor in and enjoy
