With 4L80E Automatic Transmission

Output Speed Sensor Circuit Code 24:

Output Speed Sensor Circuit:

Circuit Description:
The output speed sensor circuit is the magnetic induction type. Gear teeth pressed on the outside diameter of the output carrier assembly induce an alternating current in the sensor. Since vehicle speed is taken from the transfer case on four wheel drive vehicles, the transmission output speed sensor signal on these units goes directly to the PCM. Code 24 will set when engine speed is above 3000 rpm and output speed sensor reading is below 200 rpm for 1.5 seconds, Park/Neutral (P/N) not selected.

Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.

1. The first test checks the output speed sensor signal at the PCM.

2. The second test directly checks the output speed sensor operation.


Diagnostic Aids:
Check all connections especially at the transmission pass-thru connector. - Intermittent Malfunctions Check input speed sensor reading. A faulty input speed sensor during start-up will cause the PCM to read output at 0 rpm.