OBD-II code · Powertrain (generic, extended)
P28F9 Exhaust Pressure Too Low Bank 1
The exhaust pressure measured on bank 1 falls below the calibrated minimum. Common causes are leaks upstream of the sensor, missing DPF substrate, or sensor calibration drift.
Is it safe to drive with P28F9?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyExhaust leak upstream of sensor
- PossibleSensor zero point drifted
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–8 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Exhaust Pressure Sensor B1, Particulate Filter, Exhaust System
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.