code 31
code 31
So my 93 400 has a strange problem that I cannot figure out. When I start it, the cel light stays lit (Code 31 - Mass Air Signal) and the car idles fine for 4-10 minutes (approx.) and then it just dies. I turn it back on and it will die a few seconds later. After a couple of tries it will either continue to die, or stumble repeatedly and then eventually smooth out and run fine. When the latter happens, the cel disappears as if nothing ever happened. Swapped MAFs with redphoenix and he is still running mine with no problems and I still have the problem with his.
Any ideas?
Any ideas?
Driver School Candidate
Joined: Mar 2010
Posts: 49
Likes: 0
From: PA
Well since the MAF swap didn't work, try unplugging the MAF all together and see if that changes the symptoms at all.
Then if that doesn't give any clarity to the situation try reseting the ECU and running the car through a drive cycle to see if the issues clear up at all.
Then if that doesn't give any clarity to the situation try reseting the ECU and running the car through a drive cycle to see if the issues clear up at all.
Forgot to mention I removed the maf and reset the ecu and it ran fine. Then I reinstalled the maf and reset it and no problems after running for 5-10 minutes. Then I tryed again the next day and back to the dieing after a few minutes of idling fine. When you say drive cycle what are you referring to?
Driver School Candidate
Joined: Mar 2010
Posts: 49
Likes: 0
From: PA
drive cycle is what the ECU requires to run non-continuous monitors that it needs information from in order to be able to map out air/fuel ratios depending on all the situations you encounter daily while driving.
Trending Topics
Update...Now the car bogs when given throttle from idle at startup and beyond. Just started the manual swap today and would like to get this fixed soon to enjoy the new trans.
ClubLexus Stories
Celebrating Lexus & Toyota from Around the Globe
8 Tips for Improving Your Hybrid or Plug-in Hybrid's Efficiency!
Michael S. Palmer
10 Best Lexus Models No One Remembers
Joe Kucinski
TRD Off-Road Premium: Best 2026 4Runner, Except This One Thing
Michael S. Palmer
Top 10 Lexus & Toyotas to Drive Before You Die!
Joe Kucinski
Top 10 Lexus/Toyotas With The LEAST 5-Year Depreciation
Joe Kucinski
Lexus LC500 Convertible Auction: A Preview of Rising Values?
Brett Foote
GX 550 vs TX 550: Best 3-Row Luxury Lexus Family Hauler
Michael S. Palmer
9 Best Lexus Models You Can Buy for Half Price (And 1 You Shouldn't!)
Joe Kucinski
2026 Lexus NX Buyer's Guide: Models, Features, Prices & More!
Brett Foote
Lexus Test Driver
Joined: Aug 2009
Posts: 1,520
Likes: 1
From: CA
I think this is the exact similar problem that was happening to my cousin's mom's car (1992 SC300). They replaced the MAF and same thing happens. Now they replaced the ECU. All is fine except now they are getting code 21 & 27. So, it could be the ECU (knock on wood).
