P0172 Diagnostic Trouble Code Discussion for March 2026
Fuel System Rich (Bank 1)
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| Help Request | Posted | |
| 1999 BMW Z3 Roadster 2.5L Excessive Emissions, Poor Fuel Economy VIN: 4USCH9338X P0172: System Too Rich Bank1. Negative -28 STFT, both banks. All 4 oxygen sensors are reading full rich at about .93v ECT reads around 200-205 fahrenheit when warm. Vehicle is in closed loop. The crazy part is if the hose connected to the valve cover is disconnected, the fuel trims go ... |
March 09, 2026 |
