GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 GMC C Sierra - 2WD 🢒 Transmission/Transaxle 🢒 Automatic Transmission - Allison 🢒 DTC P2810

Circuit Description

G solenoid is a normally-closed (N/C) solenoid used to modulate the transmission main pressure. Under specific conditions, low throttle setting, low engine torque, low engine speed, and low transmission output speeds, the transmission control module (TCM) commands the G solenoid on.

When G solenoid is applied, fluid is routed to the main pressure regulator valve; this in turn reduces the main pressure schedule and improves the volume of oil through the overage circuit. By modulating main pressure, cooler flow at idle can be increased allowing improved cooling and reducing transmission pump noise.

DTC P2810 is a type B DTC.

Conditions for Running the DTC
    • The components are powered and ignition voltage is greater than 9.0 volts and less than 18 volts.
    • TCM initialization is in process or engine speed is greater than 200 RPM and less than 7,500 RPM for 5 seconds.
    • The TCM must auto-detect G solenoid.

Conditions for Setting the DTC

DTC P2810 is set when the TCM detects an open circuit, short to ground, or short to power at G solenoid circuit for greater than 2 seconds.

Action Taken When the DTC Sets
    • The TCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
    • DTC P2810 will be stored in TCM history.

Conditions for Clearing the DTC

A scan tool can clear the code from TCM history. The TCM automatically clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without failure.

Diagnostic Aids
    • Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:
       - A bent terminal
       - A backed-out terminal
       - A damaged terminal
       - Poor terminal tension
       - A chafed wire
       - A broken wire inside the insulation
    • When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.
    • You may have to drive the vehicle in order to experience a condition.
    • Solenoids are sensitive to battery voltage spikes and poor ground connections.

Test Description

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

  1. This step tests ignition voltage.

    2.

  2. This step tests the command signal from the TCM.

    3.

  3. This step tests the resistance value of the external harness and solenoid.

    4.

  4. This step tests the resistance value of the solenoid, and tests the internal wiring harness for open/shorts.

    5.

  5. This step tests the resistance value of the solenoid.

Step

Action

Value

Yes

No

Schematic Reference: Automatic Transmission Controls Schematics

1

Did you perform the Diagnostic System Check - Automatic Transmission?

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Go to Step 2

Go to Diagnostic System Check - Automatic Transmission

2

  1. Install the scan tool.
  2. Start the engine.

    3. Important: Before clearing the DTC, 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 Record Records.
  4. Clear the DTC.
  5. Using the scan tool, observe ignition voltage.

Is the voltage within the specified range?

9-18 V

Go to Step 3

Go to DTC P0562 for low voltage or DTC P0563 for high voltage

3

  1. Turn the ignition OFF.
  2. Disconnect the C2 connector (RED) at the TCM.
  3. Install the J 39700 breakout box and the J 43799 breakout box adapter.
  4. Using a DMM, measure voltage between connector C2 terminal 30 and terminal 32.
  5. Turn the ignition ON, with the engine OFF.
  6. Using the scan tool, command G solenoid to ON.

Is the voltage within the specified range when G solenoid is commanded ON.

B+

Go to Step 4

Go to Step 10

4

  1. Turn the ignition OFF.
  2. Using a DMM, measure the resistance between connector C2 terminal 30 and terminal 32.

Is the resistance reading within the specified range?

22.0 ohms @ 20°C (68°F)

Go to Diagnostic Aids

Go to Step 5

5

  1. Turn the ignition OFF.
  2. Connect the C2 connector (RED) at the TCM.
  3. Disconnect the wiring harness from the transmission 20-way connector.
  4. Using a DMM, measure resistance on the transmission side of the 20-way connector terminals R and S.

Is the resistance within the specified range?

22.0 ohms @ 20°C (68°F)

Go to Step 6

Go to Step 7

6

Inspect the engine wiring harness circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct a condition?

--

Go to Step 11

--

7

  1. Connect the transmission 20-way connector.
  2. Remove the oil pan. Refer to Oil Pan Replacement .
  3. Remove the AT internal wiring harness at G solenoid connector.
  4. Using a DMM, measure the resistance of G solenoid.

Is the solenoid resistance within the specified value?

22.0 ohms @ 20°C (68°F)

Go to Step 8

Go to Step 9

8

Replace the AT internal wiring harness. Refer to Wiring Harness Replacement .

Did you complete the replacement?

--

Go to Step 11

--

9

Replace G solenoid. Refer to Control Valve Solenoid Replacement .

Did you complete the replacement?

--

Go to Step 11

--

10

Important: In most cases, the TCM is not at fault. Investigate thoroughly before replacing the TCM.

Replace the TCM. Refer to Transmission Control Module Replacement .

Did you complete the replacement?

--

Go to Step 11

--

11

Perform the following procedure in order to verify the repair:

  1. Clear the DTC.
  2. Drive the vehicle under normal operating conditions.
  3. Select Specific DTC.
  4. Enter DTC P2810.

Has the test run and passed?

--

System OK

Go to Step 1