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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2006 🢒 G6 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 DTC P1750

Object Number: 40580 Size: MF
Master Electrical Component List
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice
Control Module References

Circuit Description

The 1-2 shift valve is used to direct fluid for shifting between first and second gear. In first gear, the 1-2 shift solenoid (1-2 SS) valve is commanded ON causing 1-2, 3-4 signal fluid pressure to overcome the 1-2 shift valve spring force, moving the 1-2 shift valve into a position that routes D4 fluid into the low/first fluid passage. In second gear, the 1-2 SS valve is commanded OFF allowing 1-2, 3-4 signal fluid to be exhausted and the 1-2 shift valve spring force then moves the 1-2 shift valve into a position that routes D4 fluid into the second fluid passage.

If the transmission control module (TCM) detects a first gear ratio when second gear is commanded indicating a stuck 1-2 shift valve, then DTC P1750 sets. DTC P1750 is a type C DTC.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P1750 1-2 Shift Valve Performance

Conditions for Running the DTC
    • No ISS DTCs P0716 or P0717.
    • The engine is running for 5 seconds or greater.
    • The vehicle speed is greater than 24 km/h (15 mph).
    • The calc. throttle position is 8 percent or greater.
    • The transmission fluid temperature is 20°C (68°F) or greater.
    • The engine torque is greater than 50 N·m (37 lb ft).

Conditions for Setting the DTC

The TCM commands second gear for 2 seconds or greater and gear ratio is 2.87:1-2.97:1 for 3.25 seconds.

Action Taken When the DTC Sets
    • The TCM does not illuminate the malfunction indicator lamp (MIL).
    • The TCM commands maximum line pressure.
    • The TCM inhibits 3-2 downshifts when the vehicle speed is greater than 52 km/h (32 mph).
    • The TCM commands a D4 shift pattern.
    • The TCM commands an alternate coast shift pattern where downshifts occur at higher vehicle speeds while coasting.
    • The TCM freezes transmission adaptive functions.
    • The TCM disables the touch activated power (TAP) shift operation.
    • The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
    • The TCM stores DTC P1750 in TCM history.

Conditions for Clearing the DTC
    • A scan tool can clear the DTC.
    • The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
    • The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

Diagnostic Aids

If DTC P1750 is cleared, then will not set again when the vehicle is driven, some of the following conditions may exist:

    • Fluid contamination
    • Plugged fluid circuits
    • Restricted fluid circuits

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Did you perform the Transmission Fluid Checking Procedure?

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Go to Step 3

Go to Transmission Fluid Check

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

    3. Important: Before clearing the DTCs, use the scan tool in order to record the Failure Records for reference. Using the Clear DTC Information function will erase the Failure Records from the TCM.

  3. Record the Freeze Frame and Failure Records.
  4. Clear the DTCs.

Is DTC P0752 also set?

--

Go to DTC P0752

Go to Step 4

4
  1. Accelerate the vehicle in D4 range, ensuring the TCM commands first, second, third, and fourth gears.
  2. With the scan tool, observe Commanded Gear and Gear Ratio for each gear.

Does the gear ratios indicate a 1-1-3-4 shift pattern?

First: 2.87:1-3.13:1

Second: 1.54:1-1.71:1

Third: 0.91:1-1.07:1

Fourth: 0.61:1-0.71:1

Go to Step 5

Go to Diagnostic Aids

5

Inspect the 1-2 shift valve/hydraulic circuit for a stuck or binding 1-2 shift valve. Refer to Symptoms - Automatic Transmission and Control Valve Body Disassemble in Transmission Unit Repair Manual.

Did you find and correct the condition?

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Go to Step 6

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6

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Information.
  3. Operate the vehicle under the following conditions:
    4. • Drive the vehicle in D4.
    • Calc. throttle position must be 8% or greater.
    • The engine torque is greater than 50 N·m (37 lb ft).
    • Ensure the gear ratio is correct for second gear for 1 second.
  4. Select Specific DTC.
  5. Enter DTC P1750.

Has the test run and passed?

Second Gear: 1.52:1-1.62:1

Go to Step 7

Go to Step 2

7

With a 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