Post Catalyst Fuel Trim System Too Rich Bank 1
Table of contents
P2097 MERCEDES-BENZ Possible Causes
- Faulty Catalytic Converter
How do I fix code P2097 MERCEDES-BENZ?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Cost of diagnosing the P2097 MERCEDES-BENZ code
The cost of diagnosing the P2097 MERCEDES-BENZ code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P2097 MERCEDES-BENZ Description
This fault code is stored in the engine control module when the ECM is no longer capable of controlling the air-fuel ratio. For correct operation of the catalytic converter, the ECM is required to keep the air-fuel ratio (AFR) at approximately lambda 1, this equates to an AFR of 14.7:1 by mass. This is achieved by trimming the fuel mixture to the required amount to cater for slight anomalies during normal operating conditions. However, when a fault causes the fuel trim to exceed a predetermined level the malfunction indicator light is illuminated, and a limited operating strategy is employed. The pre-catalyst exhaust gas oxygen sensor is the primary component used for calculating the fuel trim once the system enters closed-loop control. The fuel trim data can be displayed as a percentage, either positive or negative.
Under this condition, the fuel trim data will display a negative value. The ECM will decrease the injection duration to counteract the excessively rich mixture. This fault can be stored due to a faulty coolant temperature sensor, excessively high fuel pressure, or a faulty fuel injector.
The fuel trim is monitored under various loads and conditions. If a load or condition is included in the fault code this can be an advantage during diagnosis. Normally a code set during idle or light load is relating to an air leak. And a code set during high or part load can be a fueling issue or an erroneous sensor signal.