GM Service Manual Online
For 1990-2009 cars only

Automatic Transmission Wiring Harness Check

Step

Action

Value(s)

Yes

No

Important: The Automatic Transmission (A/T) Wiring Harness Assembly Check cannot be used for checking the automatic transmission fluid pressure (TFP) manual valve position switch circuit. Refer to Automatic Transmission Fluid Pressure Manual Valve Position Switch Resistance Check for those circuits.

1

  1. Install the J 39775 jumper harness on the transmission 20-way connector.
  2. Using the J 39200 DMM, and a J 35616-A connector test adapter kit , measure the resistance between terminals A and E (1-2 shift solenoid valve).

Is the resistance within the values indicated?

19-24Ω @ 20°C (68°F)

24-31Ω @ 100°C

(212°F)

Go to Step 3

Go to Step 2

2

  1. Disconnect the 1-2 shift solenoid (SS) valve from the automatic transmission (A/T) wiring harness assembly.
  2. Using the DMM, measure the resistance of the 1-2 SS valve.

Is the resistance within the values indicated?

19-24Ω @ 20°C (68°F)

24-31Ω @ 100°C

(212°F)

Go to Step 12

Go to Step 14

3

Measure the resistance between terminals B and E (2-3 shift solenoid valve).

Is the resistance within the values indicated?

19-24Ω @ 20°C (68°F)

24-31Ω @ 100°C

(212°F)

Go to Step 5

Go to Step 4

4

  1. Disconnect the 2-3 shift solenoid (SS) valve from the A/T wiring harness assembly.
  2. Using the DMM, measure the resistance of the 2-3 SS valve.

Is the resistance within the values indicated?

19-24Ω @ 20°C (68°F)

24-31Ω @ 100°C

(212°F)

Go to Step 12

Go to Step 14

5

Measure the resistance between terminals S and E (torque converter clutch pulse width modulation solenoid valve).

Is the resistance within the values indicated?

10-11Ω @ 20°C (68°F)

13-15Ω @ 100°C (212°F)

Go to Step 7

Go to Step 6

6

  1. Disconnect the torque converter clutch pulse width modulation (TCC PWM) solenoid valve from the A/T wiring harness assembly.
  2. Using the DMM, measure the resistance of the TCC PWM solenoid valve.

Is the resistance within the values indicated?

10-11Ω @ 20°C (68°F)

13-15Ω @ 100°C (212°F)

Go to Step 12

Go to Step 14

7

Measure the resistance between terminals C and D (pressure control solenoid valve).

Is the resistance within the values indicated?

3-5Ω @ 20°C (68°F)

4-7Ω @ 100°C (212°F)

Go to Step 9

Go to Step 8

8

  1. Disconnect the pressure control (PC) solenoid valve from the A/T wiring harness assembly.
  2. Using the DMM, measure the resistance of the PC solenoid valve.

Is the resistance within the values indicated?

3-5Ω @ 20°C (68°F)

4-7Ω @ 100°C (212°F)

Go to Step 12

Go to Step 14

9

Measure the resistance between terminals L and M (transmission fluid temperature sensor).

Is the resistance within the values indicated?

3333-3689Ω @ 20°C (68°F)

167-189Ω @ 100°C (212°F)

Go to Step 10

Go to Step 12

10

Measure the resistance from terminals A, B, C, D, E, L, M, N, P, R and S of the A/T wiring harness assembly at the transmission 20-way connector, to the transmission case.

Is the resistance measured greater than the value indicated?

250kΩ

System OK

Go to Step 11

11

  1. Disconnect the A/T wiring harness assembly from all the components.
  2. Measure the resistance from all the components terminals to the transmission case.

Is the resistance measured greater than the value indicated?

250kΩ

Go to Step 12

Go to Step 14

12

Inspect for high resistance or a shorted condition:

    • Inspect the A/T wiring harness assembly for poor electrical connections at the transmission 20-way connector and at the component connectors.
    • Look for possible bent, backed out, deformed, or damaged terminals.
    • Inspect for reduced terminal tension.
    • Inspect for chafed wire that could short to bare metal or other wiring.
    • If diagnosing for a possible intermittent condition, move or massage the A/T wiring harness assembly while observing the test equipment for a change.

Was high resistance or a shorted condition found?

--

Go to Step 1

Go to Step 13

13

Replace the A/T wiring harness assembly.

Is the replacement complete?

--

Go to Step 1

--

14

Replace the faulty component.

Is the replacement complete?

--

Go to Step 1

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