P0897: Transmission Fluid Deteriorated

What does P0897 mean?

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. Its oil life monitor counts down the remaining fluid life from operating hours, distance, shifts and load factors such as fluid temperature, open converter and retarder use. With little life remaining, TRANS SERVICE shows for two minutes after every start; if the change and reset do not follow within a set period, CHECK TRANS lights and P0897 becomes active. Correct calculation assumes approved fluid (TES 295/668).

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• CHECK TRANS lamp on
• TRANS SERVICE or wrench indicator after each start beforehand
• Driving usually normal

Common causes

• High Fluid change interval exceeded
• Medium Fluid changed without resetting the oil life monitor
• Medium Heavy duty (heat, stop-and-go, retarder) shortens calculated life
• Low Prognostics disabled afterwards (Allison special case)

Likelihood is a general estimate across vehicles; your make and model may differ.