GM Service Manual Online
For 1990-2009 cars only

4L80-E Transmission Internal Wiring Harness Check

Step

Action

Value(s)

Yes

No

1

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

Is the resistance within the values indicated?

20-40ohms

Go to Step 3

Go to Step 2

2

  1. Disconnect the internal transmission harness from the 1-2 shift solenoid valve.
  2. Using the DVOM, measure the resistance of the 1-2 shift solenoid valve.

Is the resistance within the values indicated?

20-40ohms

Go to Step 9

Go to Step 13

3

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

Is the resistance within the values indicated?

20-40ohms

Go to Step 5

Go to Step 4

4

  1. Disconnect the internal transmission harness from the 2-3 shift solenoid valve.
  2. Using the DVOM, measure the resistance of the 2-3 shift solenoid valve.

Is the resistance within the values indicated?

20-40ohms

Go to Step 9

Go to Step 13

5

Measure the resistance between terminals E and S (TCC solenoid valve).

Is the resistance within the values indicated?

10-15ohms

Go to Step 7

Go to Step 6

6

  1. Disconnect the internal transmission harness from the TCC solenoid valve.
  2. Using the DVOM, measure the resistance of the TCC solenoid valve.

Is the resistance within the values indicated?

10-15ohms

Go to Step 9

Go to Step 13

7

Measure the resistance between terminals C and D (PC Sol. Valve).

Is the resistance within the values indicated?

3.5-8ohms

Go to Step 12

Go to Step 8

8

  1. Disconnect the internal transmission harness from the Pressure Control solenoid valve.
  2. Using the DVOM, measure the resistance of the Pressure Control solenoid valve.

Is the resistance within the values indicated?

3.5-8ohms

Go to Step 9

Go to Step 13

9

Using the DVOM and the J 35616-A , measure the resistance of the Automatic Transmission Wiring Harness from the transmission 20-way connector to ground.

Is a short to ground indicated?

--

Go to Step 10

Go to Step 11

10

Repair the short to ground in the Automatic Transmission Wiring Harness. Refer to Electrical Diagnosis.

Is the repair complete?

--

Verify the repair and exit the table.

--

11

Repair the open in the Automatic Transmission Wiring Harness. Refer to Electrical Diagnosis.

Is the repair complete?

--

Verify the repair and exit the table.

--

12

  1. Inspect the transmission wiring for poor electrical connections at the transmission 20-way connector and at the component connector. Look for terminals that may be bend, backed out, deformed, or damaged. Check for weak terminal tension.
  2. Check for a chafed wire that could short to bare metal or to other wiring.
  3. If diagnosing for a possible intermittent short or for an open condition, move or massage the wiring harness while you observe the test equipment for a change in reading.

Was a problem found and corrected?

--

Verify the repair and exit the table.

--

13

Replace the component.

is the replacement complete?

--

Verify the repair and exit the table.

--