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Component & Wiring Harness Resistance Check

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  1. Install Jumper Harness (J-39775) to transmission 20-pin connector. Using an ohmmeter, measure resistance between specified terminals for each component. See Fig 1. Compare resistance reading to known values. See TRANSMISSION COMPONENT RESISTANCE SPECIFICATIONS  table.
  2. If resistance reading is okay, go to next step. If resistance reading is not okay, disconnect wiring harness at component and measure component resistance. Replace component if resistance is not as specified. If resistance is as specified, repair wiring harness between component and 20-pin connector.
  3. Measure resistance between ground and each terminal at transmission 20-pin connector. See Fig 1. Resistance should be less than 200 ohms for each component. Resistance for fluid temperature sensor will vary with temperature. If resistance is within specification, problem is intermittent. If resistance is low, disconnect wiring harness at component.
  4. Measure resistance between component terminals and ground. If resistance is low, replace component. If resistance is high, inspect wiring harness for short to ground. Repair as necessary.
TRANSMISSION COMPONENT RESISTANCE SPECIFICATIONS

Component Ohms
Input & Output Shaft Speed Sensor 1042-2088
Pressure Control Solenoid 3-8
TCC PWM Solenoid 10-15
TFT Sensor
At 68°F (20°C) 3333-3689
At 212°F (100°C) 167-189
1-2 & 2-3 Shift Solenoids 20-40
Fig 1: Identifying Component & Connector Terminal Locations
G96F04473Courtesy of GENERAL MOTORS CORP.
NOTE: Pressure switch assembly is also referred to as Transmission Fluid Pressure (TFP) Valve Position Switch.