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Makes 🢒 Chevrolet 🢒 1999 🢒 Chevy P32 RV/Van Chassis 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 4L80-E 🢒 DTC 81 2-3 Shift Solenoid Valve Circuit Electrical

DTC 81 2-3 Shift Solenoid Valve Circuit Electrical L57 MFI


Object Number: 372648 Size: MF
Automatic Transmission Components Diesel
Automatic Transmission Controls Schematics TCM Control
Handling ESD Sensitive Parts Notice

Circuit Description

The 2-3 shift solenoid (2-3 SS) valve controls fluid acting on the 2-3 shift valve. The 2-3 SS valve is a normally-open exhaust valve used with the 1-2 shift solenoid (1-2 SS) valve in order to allow four different shifting combinations. The 2-3 SS valve attaches to the control valve body within the transmission. The ignition voltage goes directly to the 2-3 SS valve. The transmission control module (TCM) controls the 2-3 SS valve by providing the ground path through circuit 1223.

If the TCM detects a continuous open or short in the 2-3 valve circuit or the 2-3 SS valve, then DTC 81 sets.

Conditions for Running the DTC
    • The ignition is ON.
    • System voltage is 12.0-16.0 volts.

Conditions for Setting the DTC
    • The TCM commands the 2-3 SS valve ON, and the voltage input remains high (B+) for 0.5 seconds.
    • The TCM commands the 2-3 SS valve OFF, and the voltage input remains low (0 volts) for 0.5 seconds.

Action Taken When the DTC Sets
    • The TCM does not illuminate the malfunction indicator lamp (MIL).
    • The TCM commands an immediate landing to second gear.
    • The TCM commands maximum line pressure.
    • The TCM stores DTC 81 in TCM history.

Conditions for Clearing the DTC
    • A scan tool clears the DTC from TCM history.
    •  The TCM clears the DTC from TCM history if the vehicle completes 40 consecutive key cycles without a diagnostic fault occurring.
    • The TCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the TCM.

Diagnostic Aids
    • Inspect the wiring at the TCM, the transmission connector and all other circuit connecting points for the following conditions:
       - A backed out terminal
       - A damaged terminal
       - Reduced terminal tension
       - A chafed wire
       - A broken wire inside the insulation
       - Moisture intrusion
       - Corrosion
    • When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.
    • First, diagnose and clear any engine DTCs or TP sensor codes that are present. Then inspect for any transmission DTCs that may have reset.
    • Refer to Shift Solenoid Valve State and Gear Ratio .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests the function of the 2-3 SS valve and the automatic transmission (A/T) wiring harness assembly.

    2.

  2. This step tests the power to the 2-3 SS valve, from the ignition through the fuse.

    3.

  3. This step tests the ability of the TCM, and the wiring, to control the ground circuit.

    4.

  4. This step measures the resistance of the A/T wiring harness assembly and the 2-3 valve.

DTC 81

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2
  1. Install the Scan Tool .
  2. With the engine OFF, turn the ignition switch to the RUN position.

    3. Important:: Before clearing the DTCs, use the scan tool in order to record the Failure Records. Using the Clear Info function erases the Failure Records from the TCM.

  3. Record the Failure Records.
  4. Clear the DTC.

Were DTC 81, 82 or 83 also set?

--

Go to Step 3

Go to Step 6

3

Inspect the transmission fuse for an open.

Refer to General Electrical Diagnosis in Wiring Systems.

Was a condition found?

--

Go to Step 5

Go to Step 4

4
  1. Inspect engine harness circuit 139 for a short to ground.
  2. Inspect the transmission wiring harness circuit 839 for a short to ground.

    3. Refer to General Electrical Diagnosis in Wiring Systems.

Was a condition found?

--

Go to Step 5

Go to Step 6

5
  1. Repair the engine harness circuit 139 if needed.

    2. Refer to Wiring Repairs in Wiring Systems.

  2. Replace the transmission wiring harness if needed.

    3. Refer to AT Wiring Harness Replacement.

Is the repair complete?

--

Go to Step 18

--

6

Command the 2-3 SS valve ON and OFF three times, while listening to the bottom of the transmission pan (use a stethoscope if needed).

Does the solenoid click when commanded?

--

Go to Diagnostic Aids

Go to Step 7

7

  1. Turn the ignition switch OFF.
  2. Disconnect the transmission 20-way connector. (Additional DTCs will set).
  3. Install the J 39775 jumper harness on the engine harness connector.
  4. With the engine OFF, turn the ignition switch to the RUN position.
  5. Connect a 12 volt test lamp from the J 39775 cavity E to ground.

Is the test lamp on?

--

Go to Step 9

Go to Step 8

8

Repair the open or high resistance in ignition feed circuit 139 (PNK).

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 18

--

9

  1. Install the test lamp between cavities E and B of the jumper on the engine harness.
  2. Using the transmission output control function, command the 2-3 SS valve ON and OFF three times.

Does the test lamp illuminate when you command the shift solenoid ON, and turn OFF when you command the shift solenoid OFF?

--

Go to Step 12

Go to Step 10

10

Inspect engine harness circuit 1223 (YEL/BLK) for an open or short to ground.

Refer to General Electrical Diagnosis in Wiring Systems.

Was a condition found and corrected?

--

Go to Step 18

Go to Step 11

11

Replace the TCM.

Refer to Powertrain Control Module Replacement/Programming in Engine Controls.

Is the replacement complete?

--

Go to Step 18

--

12

  1. Turn the ignition switch OFF.
  2. Install J 39775 on the transmission 20-way connector.
  3. With the J 39200 digital multimeter (DMM) and the J 35616 connector test adapter kit, measure the resistance between terminals B and E.

Is the resistance within the specified values?

19-31ohms

Go to Step 14

Go to Step 13

13
  1. Disconnect the automatic transmission wiring harness assembly from the 2-3 SS valve
  2. Measure the resistance of the 2-3 SS valve.

Is the resistance within the specified values?

19-31ohms

Go to Step 16

Go to Step 17

14
  1. Measure the resistance between terminal B and a good ground. Use the J 39200 DMM.
  2. Measure the resistance between terminal E and a good ground.

Are both readings greater than the specified value?

250 k

Go to Diagnostic Aids

Go to Step 15

15
  1. Disconnect the automatic transmission wiring harness assembly from the 2-3 SS valve.
  2. Measure the resistance from each of the component's terminals to ground.

Are both readings greater than the specified value?

250 k

Go to Step 16

Go to Step 17

16

Replace the automatic transmission wiring harness assembly.

Refer to Automatic Transmission Wiring Harness Replacement.

Is the replacement complete?

--

Go to Step 18

--

17

Replace the 2-3 SS valve.

Refer to 1-2 Shift Solenoid Valve Replacement.

Is the replacement complete?

--

Go to Step 18

--

18

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Operate the vehicle in D4 to ensure all commanded shifts occur.

Did all shifts occur as commanded?

--

System OK

Go to Step 1