My Son recently was on his way to work when he noticed the engine wouldn't respond when he'd press the accelerator pedal when the light he was waiting at went green. I took my scan tool and found a P2196 code along with a P0420 code. I took the vehicle out today for a test drive to get the engine warm since he only works a couple miles from the house and I thought it may be a cold engine issue, but while I was driving and on the highway, there would be times that the engine is still running, but does absolutely nothing when I press the accelerator pedal. So I began to feather the accelerator and eventually it responded and jerked like it finally found a gear.
I'm really at a loss as to what's going on here. I know the codes are related to either the oxygen sensors or catalytic converter or MAF sensor or a vacuum leak and on and on and on. I do have a cheap CReader scan tool that can get live data from the 2 Oxygen sensors on the car, but my issue is I don't know how to make heads or tails of this data to even know what I'm looking at. I've got an upstream o2 sensor from Bosch on the way as I believe this may be the culprit. But boy, would I love to know how to understand the live stream data of my scan tool to pinpoint exactly what's going on with the o2 sensors.
Thanks
If you could provide the data, Short and Long Term Fuel Trims,
O2 readings and Cat temperature maybe we can help you out.
@oneimich
Does the data need to derive from when the car is at operating temperature, or any specific RPM range for any given time? I've watched a few videos online that show holding RPM at around 2,000 or so for x amount of time to test a particular part. I just want to make sure I'm providing relevant data.
On your scanner, once the car is in closed loop hour ready to loo, at data.
How many 02 sensors are in this engine?
@oneimich
I believe the car has a pre-cat o2 sensor and post-cat o2 sensor and no more. I found a few very good videos on YouTube talking about how to properly capture and understand the data when looking at STFT and LTFT. I'll post the results of those tests today to share.
Sorry, your ready to. Go
So, here's the data I gathered.
With a cold engine at idle (750 RPM'ish, steady):
STFT-Bank 1 = 25.0%
LTFT-Bank 1 = 0.0%
STFT-Bank 2 = 99.2%
This data remains true at idle once vehicle reaches operating temperature and does not budge.
Now, when engine is held @ 2,500 RPM for a few minutes:
STFT-Bank 1 +10.2% for most of the time, eventually goes into the negative then back to positive but holds these values for 45 secs back and forth.
LTFT-Bank 1 = 0.0%
STFT-Bank 2 = 99.2%
So it seems the only thing that is changing when the engine is at operating temps and RPM held @ 2,500 is the STFT-Bank 1. Not going to lie and pretend I know what this indicates, so any suggestions would be much appreciated!
Some additional information.
This time I monitored my O2 sensors at idle and at 2,500 RPM. Here is the data:
B1-S1 O2 Sensor @ Idle Operating Temps fluctuates around 0.05 to 0.9mA
B1-S2 O2 Sensor @ Idle Operating Temps is fluctuates around 0.275V to 0.290V
B1-S1 O2 Sensor @ 2,500 RPM fluctuates around 0.310V to 0.325V
B1-S2 O2 Sensor @ 2,500 RPM fluctuates around -0.08 to 0.02mA
Here is the Freeze Frame data:
DTC that caused required freeze frame data storage - P0420
Fuel system 1 status - CL
Fuel system 2 status - ---
Calculated LOAD Value - 55.7%
Engine Coolant Temp - 199F
Short Term Fuel Trim Bank 1 - -0.8%
Long Term Fuel Trim Bank 1 - 3.1%
Engine RPM - 1557/min
Vehicle Speed - 31mph
Ignition Timing Advance for #1 Cylinder - 19.5 degree
Intake Air Temperature - 75F
Air Flow Rate from Mass Air Flow Sensor - 1.9lb/min
Absolute Throttle Position - 20.0%
Commanded Secondary Air Status - OFF
I just noticed that my fuel system status 1 is showing a CL_Fault. Would this mean that the vehicle is running on just 1 O2 sensor (B1S1) and I should look into replacing that?
I feel as though I'm just talking into the void at this point. I'm just going to go with purchasing a new o2 sensor and hope it resolves the issue. If it works, I'll be sure to update this post in hopes it can help someone else in the future.
I've decided to do a smoke test to test for vacuum leaks before opening the box on this new upstream o2 sensor. While the data seems to indicate (at least to me) that there is an upstream o2 sensor issue, I feel as though I have a vacuum leak somewhere in this vehicle that is causing issues as well. I've got me a smoke tester coming from Amazon over the next few days and plan on sharing the results from that.