Diagnostic Aids

WARNING: This page is about a different car, the 2003 GMC Sonoma, 2003 GMC Jimmy, 2003 Chevrolet S10 Pickup, and 2003 Chevrolet Blazer. However, it is still accessible from the selected car via links, so may be relevant.

Refer to the TRANSMISSION FLUID PRESSURE (TFP) MANUAL VALVE POSITION SWITCH LOGIC table for the normal range signals and the invalid combinations. On the table, LOW is 0 volts, HI is ignition voltage.
Ensure that the transmission linkage from the select lever to the manual valve is adjusted/connected properly.
Sediment in the valve body may cause improper operation of the TFP manual valve position switch. If sediment intrusion is suspected, clean the valve body and replace the TFP manual valve position switch.