GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1996 🢒 Tahoe - 4WD 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 4L60-E 🢒 Pressure Switch Assembly Resistance Check

Test Description

Tools Required

    • J 39775 4L60-E Jumper Harness
    • J 39200 Digital Multimeter
    • J 35616-A Connector Test Adapter Kit

Important: Whenever the transmission 20-way connector is disconnected and the engine is running, multiple DTCs will set. Be sure to clear these codes when you are finished with this procedure.

Important: This procedure tests the Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.) circuits and the Automatic Transmission Fluid Temperature (TFT) Sensor circuit. Do not use this procedure to test other Automatic Transmission circuits. Refer to 4L60-E Automatic Transmission Wiring Harness Check

TFP Valve Position Switch Resistance Check

Step

Action

Value(s)

Yes

No

1
  1. Install the J 39775 Jumper Harness on the transmission side of the 20-way connector.
  2. Using the J 39200 Digital Multimeter (DMM) and the J 35616-A Connector Test Adapter Kit, measure the resistance from terminal N to the transmission case.

Is the resistance greater than the specified value?

50 K ohms

Go to Step 3

Go to Step 2

2
  1. Disconnect the TFP Val. Position Sw. from the Automatic Transmission Wiring Harness Assembly (A/T Wiring Harness Assembly).
  2. Measure the resistance from terminal C of the TFP Val. Position Sw. to the switch housing.

Is the resistance greater than the specified value?

50 K ohms

Go to Step 16

Go to Step 19

3

Measure the resistance from terminal R to the transmission case.

Is the resistance less than the specified value?

200 ohms

Go to Step 5

Go to Step 4

4
  1. Disconnect the TFP Val. Position Sw. from the A/T Wiring Harness Assembly.
  2. Measure the resistance from terminal E of the TFP Val. Position Sw. to the switch housing.

Is the resistance less than the specified value?

200 ohms

Go to Step 16

Go to Step 19

5

Measure the resistance from terminal P to the transmission case.

Is the resistance greater than the specified value?

50 K ohms

Go to Step 7

Go to Step 6

6
  1. Disconnect the TFP Val. Position Sw. from the A/T Wiring Harness Assembly.
  2. Measure the resistance from terminal D of the TFP Val. Position Sw. to the switch housing.

Is the resistance greater than the specified value?

50 K ohms

Go to Step 16

Go to Step 19

7
  1. Start the engine.
  2. Allow the engine to idle.
  3. Set the parking brake.
  4. Place the gear selector in Reverse.
  5. Measure the resistance from terminal N to the transmission case.

Is the resistance less than the specified value?

200 ohms

Go to Step 8

Go to Step 16

8
  1. Place the gear selector in Low (D1).
  2. Measure the resistance from terminal N to the transmission case.

Is the resistance less than the specified value?

200 ohms

Go to Step 9

Go to Step 16

9
  1. Place the gear selector in Manual Third (D3).
  2. Measure the resistance from terminal R to the transmission case.

Is the resistance greater than the specified value?

50 K ohms

Go to Step 10

Go to Step 16

10
  1. Place the gear selector in Drive (D4).
  2. Measure the resistance from terminal P to the transmission case.

Is the resistance less than the specified value?

200 ohms

Go to Step 11

Go to Step 16

11
  1. Place the gear selector in Manual Second (D2).
  2. Measure the resistance from terminal P to the transmission case.

Is the resistance greater than the specified value?

50 K ohms

Go to Step 12

Go to Step 16

12
  1. Turn the ignition OFF.

    2. Important: The resistance of the TFT Sensor is temperature dependent, and therefore varies far more than any other device. Refer to Transmission Fluid Temperature Sensor in Electronic Component Description .

  2. Measure the resistance from terminal L to terminal M (TFT Sensor) of the J 39775 Jumper Harness.

Is the resistance within the specified range?

3088-3942 ohms @ 20°C (68°F)

159-198 ohms @ 100°C (212°F)

Go to Step 13

Go to Step 14

13
  1. Measure the resistance from terminal L to the transmission case.
  2. Measure the resistance from terminal M to the transmission case.

Are both resistances greater than the specified value?

10 M ohms

No condition found. Exit the table.

Go to Step 14

14
  1. Disconnect the TFP Val. Position Sw. from the A/T Wiring Harness Assembly.

    2. Important: The resistance of the TFT Sensor is temperature dependent, and therefore varies far more than any other device. Refer to Transmission Fluid Temperature Sensor in Electronic Component Description .

  2. Using the J 39200 DMM, measure the resistance between terminal A and terminal B of the TFP Val. Position Sw. (TFT Sensor).

Is the resistance within the specified range?

3088-3942 ohms @ 20°C (68°F)

159-198 ohms @ 100°C (212°F)

Go to Step 15

Go to Step 19

15
  1. Measure the resistance from TFP Val. Position Sw. terminal A to the transmission case.
  2. Measure the resistance from TFP Val. Position Sw. terminal B to the transmission case.

Are both resistances greater than the specified value?

10 M ohms

Go to Step 16

Go to Step 19

16

Inspect for high resistance or a short:

    • Inspect the A/T Wiring Harness Assembly. for poor electrical connections at the automatic transmission 20-way connector, and at the TFP Val. Position Sw. Look for the following conditions:
       - A backed out terminal
       - A damaged terminal
       - A bent terminal
       - Poor terminal tension
       - A chafed wire
       - A broken wire inside the insulation
       - Moisture intrusion
       - Corrosion
    • If diagnosing for an intermittent condition, massage the wiring harness while watching the test equipment for a change.

Did you find high resistance or a short?

--

Verify the repair. Go to Step 1

Go to Step 17

17
  1. Disconnect the TFP Val. Position Sw. from the A/T Wiring Harness Assembly.
  2. Inspect the following circuits for an open or short:
    3. • Circuit 1224
    • Circuit 1225
    • Circuit 1226
    • Circuit 1227

Did you find an open or shorted condition?

--

Go to Step 18

Go to Step 19

18

Replace the A/T Wiring Harness Assembly.

Refer to TCC PWM Solenoid, TCC Solenoid, and Wiring Harness Replacement.

Is the replacement complete?

--

Verify the repair. Go to Step 1

--

19

Replace the TFP Val. Position Sw.

Refer to Valve Body and Pressure Switch Replacement.

Is the replacement complete?

--

Verify the repair. Go to Step 1

--