Failed Emissions
Martin
Joined: Jan 2011
Posts: 3,036
Likes: 260
From: Lehi, Utah
As I'm sure your aware the codes will fire in order so if the first ones were fixed the others would most likely go off. Sometimes the later codes can be completely Illrelevant. The first couple codes seem like not enough vacuum to me.
Thread Starter
Junior Member
Joined: Oct 2011
Posts: 15
Likes: 0
Hi. I have a 96 f150 4x4 w/dual tanks & an inline 6 4.9 and I just failed emissions. And they gave me these 4 reasons. Im lost and if anyone can help i would love it. Reason 1. P0411 "SECONDARY AIR INJECTION SYSTEM INCORRECT FLOW DETECTED. Reason 2. P0401 EXHAUST GAS RECIRCULATION FLOW INSUFFICIENT DETECTED. Reason 3. P0171 SYSTEM TOO LEAN (BANK 1)(2). Reason 4. P0174 SYSTEM TOO LEAN (BANK 2).
First thx for all the advice from everyone! Turns out I had a 5th problem on my 2nd attempted pass. My check engine light would not come on. The 1st inspection they missed it. Anyway I FINALLY PASSED on my 4th try. Here's what I did to make pass.
1. TO FIX NO CHECK ENGINE LIGHT. I Had to tear apart my dash (this was not hard but so time consuming). There was a bad connector for that bulb, so I replaced it and prob fixed.
2. TO FIX THE OTHER PROBLEMS (Not sure what fixed what though). I inspected all the vac line hoses again and even though they were practically new, one was connected to a wrong intake vac hose. I easily fixed that one.
3. Cleaned out the MAS w/Mass airflow sensor cleaner.
4. Cleaned and oiled the air filter.
5. Put a new TPS on.
6. Cleaned the EGR.
7. Crossed my fingers and passed w/flying colors.
HOPE THIS HELPS SOMEONE ELSE TOO
Thx again everyone.
