2014 Mercedes E350 P2190 System Too Rich at Idle Bank 2

Question

My E350 just threw a check engine light and it has a noticeable stumble once I come to a complete stop at red lights. The car runs perfectly fine at highway speeds, but the idle feels very hunt-y and unstable. Scan tool is showing P2190 permanently stored for Bank 2.

Brian O'Connor · Accepted Answer

The issue was a leaking High-Pressure Fuel Pump (HPFP) on the Bank 2 side. I pulled the pump and found fuel had been bypassing the internal piston seal into the camshaft housing. I replaced the pump with a Bosch OEM unit (Part # 0261520215) and changed the oil to remove the fuel dilution. After clearing adaptations, the fuel trims returned to +/- 2% and the idle is now rock solid. Total part cost was about $480.

road_rambler · Answer

On the M276 engine, P2190 at idle usually points towards a leaking high-pressure fuel pump or an injector that isn't sealing. Since it's only Bank 2, you should check your short-term fuel trims at idle to see how far they are pulling fuel away.

garagegrease · Answer

Pull the oil dipstick and smell the oil for gasoline. If the high-pressure fuel pump (HPFP) internal seal fails, it leaks raw fuel directly into the crankcase, which then gets sucked through the PCV system, causing a rich condition primarily at idle.

turbo_tony · Answer

Check the purge valve (MOT valve) on the front of the engine. If it is stuck open, it will dump fuel vapors from the charcoal canister into the intake manifold constantly, causing the computer to lean out the mixture to compensate.

2014 Mercedes E350 P2190 System Too Rich at Idle Bank 2

Suggest a repair