2015, 1.4 liter, Hatchback LTZ, Manual transmission
Scan gage shows pending code p0131. Eventually it pops up as a hard fault with the CEL illuminated.
Engine at first ran rough like it's on three cylinders.
This all happened after I replaced the thermostat and the water outlet manifold. Checked all connections and they are clean. I replaced the thermostat for preventative maintenance and the outlet manifold had a seep from under the upper radiator hose. Flushed the coolant and renewed. So I replaced the forward O2 sensor and it cleared up. The engine runs smooth as can be. After a minute or so when warmed up I get a slight miss for a second and then is good again. After monitoring my scan gage that slight miss is when the scan gage goes from closed loop to open loop and the pending fault of p0131 pops up again.
My coolant temperature indication is normal, cooling fan operates normal. High and low speed as well as when AC is turned on. I replaced the PCV breather hose from intake manifold to turbo inlet. The built in check valve on the hose was not sealing fully. It was bypassing. This check valve is on the end that connects to the turbo inlet side. I also pressure tested the old hose and it had no leaks. I still replaced it because they are prone to failure. In my case the check valve failed. I pulled the oil dipstick out and the engine shutters while struggling to run and same thing when I pulled the oil filler cap. I already did the pcv modification using the external check valve kit.
I have vacuum and normal coolant temps. Something is triggering this fault code. I even thought about a bad O2 sensor from stock. The connections look clean and no visible signs of frayed or damaged wires and connectors. The only code I have is p0131. No others. Any suggestions would be appreciated.
The engine runs, its driveable as normal as can be. The fault code keeps popping up as pending and then it will trigger the CEL. I keep clearing the fault but it returns everytime.
Thanks for taking the time to read my post
Scan gage shows pending code p0131. Eventually it pops up as a hard fault with the CEL illuminated.
Engine at first ran rough like it's on three cylinders.
This all happened after I replaced the thermostat and the water outlet manifold. Checked all connections and they are clean. I replaced the thermostat for preventative maintenance and the outlet manifold had a seep from under the upper radiator hose. Flushed the coolant and renewed. So I replaced the forward O2 sensor and it cleared up. The engine runs smooth as can be. After a minute or so when warmed up I get a slight miss for a second and then is good again. After monitoring my scan gage that slight miss is when the scan gage goes from closed loop to open loop and the pending fault of p0131 pops up again.
My coolant temperature indication is normal, cooling fan operates normal. High and low speed as well as when AC is turned on. I replaced the PCV breather hose from intake manifold to turbo inlet. The built in check valve on the hose was not sealing fully. It was bypassing. This check valve is on the end that connects to the turbo inlet side. I also pressure tested the old hose and it had no leaks. I still replaced it because they are prone to failure. In my case the check valve failed. I pulled the oil dipstick out and the engine shutters while struggling to run and same thing when I pulled the oil filler cap. I already did the pcv modification using the external check valve kit.
I have vacuum and normal coolant temps. Something is triggering this fault code. I even thought about a bad O2 sensor from stock. The connections look clean and no visible signs of frayed or damaged wires and connectors. The only code I have is p0131. No others. Any suggestions would be appreciated.
The engine runs, its driveable as normal as can be. The fault code keeps popping up as pending and then it will trigger the CEL. I keep clearing the fault but it returns everytime.
Thanks for taking the time to read my post