P088BTransmission Fluid Filter Very Deteriorated
- Generic OBD-II code · Powertrain
- How the car detects it
- Allison's 'Prognostics' in its fourth and fifth generation controls (1000 to 4000 series, buses and trucks, from 2009) has no fluid quality sensor: the gearbox module calculates. No car maker is known to use these codes. P088B is the second stage of the filter life monitor: the filter counts as heavily clogged or its change as overdue, and the CHECK TRANS lamp comes on. Isuzu names it the most common reason for that lamp on its Allison trucks, a maintenance item rather than a gearbox defect. Allison's patent allows limiting gearbox functions at this stage; the bulletins describe only the warning. Change the filter and reset the monitor.
- What you may notice
- CHECK TRANS lamp on
- Message to service the transmission filter
- Rarely a gear limit
- Likely causes
- LikelyFilter change overdue
- PossibleMonitor not reset after the change
- PossibleIncreased internal wear debris
- RareFaulty main valve body (Allison)
- Repair
- Easy · Often possible to do yourself.Typical cost: €60 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.