13 Hyundai Post Catalyst Lean
Came in a year ago with the P2096 Post Catalyst fuel trim lean, replaced the post cat O2 and re flashed the ECM per the TSB. Came back a short time ago with a P2096 and P2196, Down stream lean, up stream rich. Got a new post cat O2 and up stream AF. Both aftermarket Denso sensors. ECM calibration checked and found current. Both codes have returned within a few days of clearing several times. No vacuum or exhaust leaks found. Fuel trim looks normal at idle, 2500 and wile driving. Total with in 10% Engine performance feels good. Strong Manifold vacuum. 20+. Good fuel pressure. Map sensor scoped good. No drop outs. Map sensor also replaced. Purge valve not leaking. I can watch the down stream O2 sensor read lean on the scanner. Happens once per key cycle at steady cruse. Event lasts for a few seconds then reading returns to around 700mv. Some times sets the codes when this happens sometimes not. Any suggestions are appreciated.
Hello, Jeremiah Not sure if this will help but I run across a issue with aftermarket sensors being mist box or they pull the wrong part looks like this unit has OEM# Front,w/calif Ecs 39210-2e400 Front,w/o calif Ecs 39210-2e500 Rear,w/ calif Ecs 39210-2e100 Rear,w/o calif Ecs 39210-2e200 Denso Sensors Upstream w/calif. 234-5082 Upstream w/o calif. 234-5083 Downstream w/o calif…
Any time you see the front sensors showing a rich condition, (more fuel than air) and the rear sensors reporting a lean condition( more air than fuel ), someone is lying, or you have an air leak in the exhaust. Get yourself a set of new OE sensors. that way you should get the correct sensors for the application. Once the sensors are baselined, You have something to work with.
Jeremaih as stated above, something is lying. For example If you have a lambda of 1 entering the engine, youll have a lambda of 1 exiting the engine and entering the cat. The Cat does not change air fuel ratio. So you should have a lambda of 1 exiting the cat. Unless you have a exhaust leak between up stream and down stream you can not have Rich on one 02 and Lean on the other 02.
In regards to; "I can watch the down stream O2 sensor read lean on the scanner. Happens once per key cycle at steady cruse. Event lasts for a few seconds then reading returns to around 700mv. Some times sets the codes when this happens sometimes not. Any suggestions are appreciated. " I think that is normal ECM strategy, it is testing. Test results must be borderline and when it fails, it trips
Whats the 5 gas telling you?