P1750

DTC P1750





Circuit Description
The 1-2 shift valve is used to direct fluid for shifting between 1st and 2nd gears. In 1st 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 Lo/1st fluid passage. In 2nd 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 2nd fluid passage.

If the PCM detects a 1st gear ratio when 2nd 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 VSS DTC P0502 or P0503.
^ No ISS DTC P0716 or P0717.
^ The engine speed is greater than 500 RPM for 5 seconds and not in fuel cut off.
^ The vehicle speed is 8 km/h (5 mph) or more.
^ The TP angle is 5 percent or more.
^ The transmission fluid temperature is 10°C (50°F) or more.
^ The engine torque is 27 - 407 Nm (20 - 300 ft. lbs.).

Conditions for Setting the DTC
The PCM commands 2nd gear and the ratio indicates 1st gear, 2.87:1 to 2.97:1 for 2 seconds.

Action Taken When the DTC Sets
^ The PCM does not illuminate the malfunction indicator lamp (MIL).
^ The PCM disables TAP Shift operation.
^ The PCM freezes transmission adaptive functions.
^ The PCM inhibits 3-2 downshifts when the vehicle speed is greater than 48 km/h (30 mph).
^ The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Failure Records.
^ The PCM stores DTC P1750 in PCM history.

Conditions for Clearing the DTC
^ A scan tool can clear the DTC.
^ The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
^ The PCM cancels the DTC default actions when the fault no longer exists and the DTC passes.

Diagnostic Aids

Step 1 - Step 5:

Step 6 - Step 7:

If DTC P1750 is cleared, then will not reset when the vehicle is driven, some of the following conditions may exist:
^ Fluid contamination
^ Plugged fluid circuits
^ Restricted fluid circuits