GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2004 🢒 VUE - AWD 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 5AT 🢒 DTC P0780

Object Number: 1246922 Size: MF
Master Electrical Component List
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice

Circuit Description

Shift valve D is incorporated into the control circuit inside the transmission. When the shift lever is in D or I range, line pressure is supplied to shift valve D, and clutch control pressure A is supplied to the 4th clutch. When the shift lever is in L range, the shift valve D is pushed by the spring D and the clutch control pressure B is supplied to the L/H clutch. Shift valve D operates upon rise in the line pressure or clutch control pressure A. Shift valve D is pushed back by the reactive force of spring D when the line pressure or clutch control pressure A drops. The PCM monitors mainshaft to output shaft speed ratio in the gear positions determined by the shift schedule. When the incorrect ratio for the commanded gear is detected, the PCM determines it as a fault and DTC P0780 sets. DTC P0780 is a type B DTC.

Conditions for Running the DTC
    • No TP DTCs P0122, P0123, P0222, or P0223.
    • No VSS DTCs P0501, P0502, or P0503.
    • No TR Switch DTC P0705.
    • No AT ISS DTCs P0716, P0717, or P0718.
    • No Clutch PC Solenoid 1 DTCs P0746 or P0747.
    • No SS Valve Performance DTCs P0751, P0752, P0756, P0757, or P0761.
    • No Clutch PC Solenoid 2 DTCs P0776 or P0777.
    • No Incorrect Shift Pattern DTC P0780.
    • No Clutch PC Solenoid Electrical DTCs P0962 or P0963.
    • No Clutch PC Solenoid 2 DTCs P0966 or P0967.
    • No SS 1 DTCs P0973 or P0974.
    • No SS 2 DTCs P0976 or P0977.
    • No SS 3 DTCs P0979 or P0980.
    • No TAC DTCs P2101, P2108, P2111, P2112, or P2553.
    • No APP DTC P2122, P2123, P2127, P2128, P2135, or P2138.
    • No Minimum Idle Position DTC P2176.
    • No TCC PC Solenoid DTCs P2763 or P2764.
    • No TCC Enable Solenoid DTCs P2769 or P2770.
    • No TAC Communication DTC U0107.
    • System voltage is greater than 11 volts.
    • Transmission fluid temperature is -25°C (-13°F) or greater.

Conditions for Setting the DTC

The transmission downshifts from 3rd to 2nd in response to a 3-4 upshift command.

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 limits the transmission shift to 2nd and 3rd gears.
    • 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 P0780 in PCM history.

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 for a stuck shift valve D.

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step inspects the transmission fluid to ensure that it is at the proper level.

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check - Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls in Engine Controls - 3.5L (L66)

2

Did you perform the Transmission Fluid Checking Procedure?

Go to Step 3

Go to Transmission Fluid Check

3
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.

    3. Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the PCM.

  3. Record the DTC Freeze Frame and Failure Records.
  4. Clear the DTC.
  5. Drive the vehicle in 5th gear at speeds above 80 km/h (50 mph).

Does the DTC reset?

Go to Step 4

Go to Diagnostic Aids

4
  1. Inspect for the following conditions:
    2. • The pressure regulator valve for being stuck due to sediment or binding
    • The shift valve D hydraulic fluid circuits for damage
    • The shift valve D for being stuck
  2. Repair any of the above conditions as necessary.

Did you complete the repair?

Go to Step 5

--

5

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Drive the vehicle in 5th gear at speeds above 80 km/h (50 mph).
  4. Select Specific DTC.
  5. Enter DTC P0780.

Has the test run and passed?

Go to Step 6

Go to Step 2

6

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) Types in Engine Controls - 3.5L (L66)

System OK