RAM 1500 2020–2021 — technical service bulletin
Bulletin 0900321 · NHTSA communication 10220987 · issued Mar 27, 2021
Technical service bulletin
communication type
Power Train
component
2020–2021
model years
2
vehicle entries
Official summary
Transmission Oil Cooler Lines Not Fully Connected This bulletin involves inspecting the Transmission Oil Cooler (TOC) lines and reconnecting if necessary. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find one or more ofthe following Diagnostic Trouble Codes (DTCs). P1D90-00 Incorrect Gear Ratio - Clutch 2 Defective. P1D91-00 Incorrect Gear Ratio - Clutch 3 Defective. P1D92-00 Incorrect Gear Ratio - Clutch 4 Defective. P1D93-00 Incorrect Gear Ratio - Clutch 5 Defective. P1D95-00 Tcm Clutch Failure Undetermined. P1B14-00
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.