GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2006 🢒 I-280 🢒 Brakes 🢒 Park Brake 🢒 DTC P2770

Object Number: 1432463 Size: LF
Master Electrical Component List
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice
Control Module References

Circuit Description

The torque converter clutch (TCC) solenoid valve is an electrical device that is used with the torque converter clutch pulse width modulation (TCC PWM) solenoid valve in order to control TCC apply and release. The TCC solenoid valve attaches to the transmission case assembly extending into the pump cover. The TCC solenoid valve receives ignition voltage through the ignition voltage circuit. The powertrain control module (PCM) controls the solenoid by providing the ground path on the TCC solenoid valve control circuit. The PCM monitors the throttle position sensor voltage, the vehicle speed, and other inputs in order to determine when to energize the TCC solenoid valve.

When the PCM detects a short to voltage in the TCC solenoid valve circuit, then DTC P2770 sets. DTC P2770 is a type B DTC.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P2770 Torque Converter Clutch (TCC) Enable Solenoid Control Circuit High Voltage

Conditions for Running the DTC
    • The engine speed is greater than 475 RPM for 5 seconds.
    • The engine is not in fuel cutoff.

Conditions for Setting the DTC

DTC P2770 sets if the following condition occurs for 5 seconds:

The PCM commands the solenoid ON and the voltage feedback remains high, B+.

Action Taken When the DTC Sets
    • The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
    • The PCM commands maximum line pressure.
    • The PCM inhibits TCC engagement.
    • The PCM inhibits 4th gear if the transmission is in hot mode.
    • The PCM freezes transmission adapt functions.
    • The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
    • The PCM stores DTC P2770 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

Conditions for Clearing the MIL/DTC
    • The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
    • A scan tool can clear the MIL/DTC.
    • The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
    • The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

Diagnostic Aids
    • Inspect the connectors at the PCM, the TCC enable solenoid valve, and all other circuit connecting points for an intermittent condition. Refer to Testing for Intermittent Conditions and Poor Connections .
    • Inspect the circuit wiring for an intermittent condition. Refer to Testing for Electrical Intermittents .
    • Inspect for a disconnected TCC enable solenoid valve connector.
    • Inspect for an open TCC enable solenoid valve circuit.
    • Inspect for a faulty TCC enable solenoid valve.
    • Inspect for a PCM internal fault.

Test Description

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

  1. During the TCC enable solenoid valve operation, listen for an audible click. Command the ON and the OFF states. Repeat the commands as necessary.

    2.

  2. This step verifies that the PCM is providing voltage to the TCC enable solenoid valve.

    3.

  3. This step tests for an open or short to another circuit within the transmission.

    4.

  4. This step tests for short voltage to the TCC enable solenoid valve.

    5.

  5. This step tests for an open in the TCC enable solenoid valve high control circuit.

DTC P2770

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Install a scan tool.
  2. Turn ON the ignition with the engine OFF.

    3. Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data.

  3. Record the DTC Freeze Frame and Failure Records.
  4. Clear the DTCs.
  5. With a scan tool, command the TCC enable solenoid valve ON and OFF.

Does the TCC enable solenoid valve turn ON and OFF with each command?

--

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the AT inline 20-way connector, additional DTCs may set.
  3. Install the J 44152 Jumper Harness (20 pins) on the engine side of the AT inline 20-way connector.
  4. Turn ON the ignition, with the engine OFF.
  5. Using the J 35616 Terminal Test Kit, connect a test lamp from the ignition voltage circuit of the J 44152 to ground. Refer to Automatic Transmission Inline 20-Way Connector End View .
  6. With a scan tool, command the TCC enable solenoid valve ON and OFF.

Does the test lamp turn ON and OFF with each command?

--

Go to Step 4

Go to Step 5

4

Test the TCC enable solenoid valve high control circuit internal transmission harness for an open or short to another circuit. Refer to Testing for Continuity .

Did you find a condition?

--

Go to Step 10

Go to Step 8

5

Does the test lamp remain illuminated with each command?

--

Go to Step 7

Go to Step 6

6

Test the TCC enable solenoid valve control circuit for an open. Refer to Testing for Continuity and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 13

Go to Step 9

7

Test the TCC enable solenoid valve high control circuit for a short to voltage. Refer to Testing for a Short to Voltage and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 13

Go to Step 9

8

Inspect for poor connections at the TCC enable solenoid valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 13

Go to Step 11

9

Inspect for poor connections at the PCM harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

10

Replace the AT wiring harness, this includes the TCC solenoid assembly. Refer to Valve Body and Pressure Switch Replacement .

Did you complete the repair?

--

Go to Step 13

--

11

Replace the TCC enable solenoid valve. Refer to Valve Body and Pressure Switch Replacement .

Did you complete the replacement?

--

Go to Step 13

--

12

Replace the PCM. Refer to Control Module References .

Did you complete the replacement?

--

Go to Step 13

--

13

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Drive the vehicle in D4 with the TCC ON and OFF.

    4. Ensure the following conditions are met:

    • The PCM commands the TCC solenoid valve ON, and the voltage feedback drops to zero.
    • The PCM commands the TCC solenoid valve OFF, and the voltage feedback increases to B+.
    • All conditions are met for 5 seconds.
  4. Select Specific DTC.
  5. Enter DTC P2770.

Has the test run and passed?

--

Go to Step 14

Go to Step 2

14

With the scan tool, observe the stored information, capture info. and DTC info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK