P2096
ModerateP2096 — Post-Catalyst Fuel Trim: System Too Lean
Description
What the Code Means
P2096 flags a fuel mixture that's too lean based on the oxygen sensor reading downstream of the catalytic converter. The control module evaluates fuel trim from the post-catalyst O2 sensor: if the mixture after the catalytic converter stays leaner than calculated, the code sets. This code falls under the EGR/DPF/SCR systems category, severity is moderate.
Common causes: exhaust leaks, catalytic converter degradation, a faulty oxygen sensor.
Symptoms
Symptoms
- Check Engine light is on;
- worse fuel economy;
- the car fails an emissions test.
Causes and fixes
Diagnosis and Repair
Work through the diagnosis in order of likely causes.
- Check the exhaust system for leaks — air getting in upstream or around the downstream O2 sensor skews its reading and leans out the measured mixture.
- Check the downstream oxygen sensor — its signal and how it responds to changes in mixture.
- Check catalytic converter efficiency — catalytic converter degradation directly affects the post-catalyst O2 sensor reading.
- If the oxygen sensor is faulty, replace it. OEM part number:
11787558095.
Possible secondary damage
Related Problems
- running lean for a long time damages the catalytic converter;
- oxygen sensors fail.
Don't put off fixing the root cause: both consequences are tied to the exhaust aftertreatment system and lead to a bigger repair.