TF10 - Check TSS Resistance

Engine Running Diagnostic Trouble Code (DTC) 639 indicates an error has been detected in the Transmission Speed Sensor (TSS) input signal.

Possible causes:
- Open or shorted harness.
- Damaged transmission speed sensor. Damaged Powertrain Control Module (PCM).

- Key "OFF".

- Disconnect transmission connector (12 pin at transmission).

Transmission Connector:

- Measure resistance between TSS(+) and TSS(-) pins at transmission 12 pin connector.

- Is resistance between 200 and 600 ohms?

Yes -- Go to TF11. TF11 - Check TSS Circuits For Short to Power

No -- Inspect transmission wiring for opens/shorts. If OK, replace transmission speed sensor. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)