Test 20A - Speed Ratio Error In Reverse & 1ST (DTC 50 & 51)

NOTE: Perform TEST 2A before proceeding with this test. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagrams, see WIRING DIAGRAMS . Perform VERIFICATION TEST VER-1A after each repair.

CAUTION: Always turn ignition switch to OFF position prior to disconnecting or connecting any module connector.

NOTE: Transmission Control Module (TCM) replacement WILL NOT correct DTC 51.

Remove and inspect input speed sensor for damage and correct installation. Replace as needed. Remove and inspect output speed sensor for damage and correct installation. Replace as needed.
Raise and support front of vehicle. Start engine. Place shifter in OD position. Allow front wheels to rotate at engine idle speed. Using scan tool, monitor input and output speed sensor RPM readings. If both sensor readings are more than zero RPM, you should go to TEST 20B . If either sensor reading is zero, you should also go to TEST 20C .