natenatec

Got a code P1757. I know what it means, I need to know how to fix it. If anyone can help, please do!

cbrahs

what year is your truck

fill out your signature so we know what we are working with


WELCOME TO THE BOARD!

cbrahs

without knowing exact year to make sure I have this right here is what ya get so far. pm me with your email addy and I can email you the PDF so you can have the diagrams too


P1757-GOV PRESS ABOVE 3 PSI IN GEAR WITH 0 MPH (DIESEL)




For a complete wiring diagramRefer to Section 8W

Theory of Operation
The Governor Pressure Control System is used to regulate the governor pressure which controls the shifts for first, second, and third gear. The Governor Pressure Control System test verifies that the requested pressure and the actual pressure are within a predetermined tolerance.

When Monitored:
While the engine is running and the gear selector is in the Drive position.

Set Condition:
This DTC will set if the monitored Governor Pressure is greater than 41.4 kPa (6 psi) for 5 seconds while the gear selector is in the Drive position with the road speed equal to zero - six times during a drive cycle. The transmission oil temperature must be between 23 - 88° C (73 - 190° F).

Possible Causes
OTHER TRANSMISSION DTC'S PRESENT
5 VOLT SUPPLY CIRCUIT OPEN
5 VOLT SUPPLY CIRCUIT OPEN INSIDE THE TRANSMISSION
TRANSMISSION OIL BURNT OR OIL PAN HAS EXCESSIVE DEBRIS - INTERNAL TRANSMISSION DAMAGE
GOVERNOR PRESSURE SENSOR
GOVERNOR PRESSURE SOLENOID
VALVE BODY
ENGINE CONTROL MODULE 5 VOLT SUPPLY
ENGINE CONTROL MODULE


Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)

Diagnostic Test
1. OTHER TRANSMISSION DTC'S PRESENT

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Ignition on, engine not running.
With the scan tool, read Engine DTCs.

Are there any other Transmission DTCs present?

Yes
Refer to the Transmission category and perform the appropriate symptom(s). (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE - DIAGNOSIS AND TESTING)

No
Go To 2



2. CHECK IF THE DTC IS CURRENT

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With the scan tool, read Engine DTCs.
Record the Freeze Frame data for the reported DTC.
With the scan tool, erase DTCs.
Turn the ignition off to the lock position.
Using the Freeze Frame data recorded earlier, try to duplicate the conditions in which the DTC originally set.

NOTE: It may be necessary to road test the vehicle to duplicate the original set conditions.


With the scan tool, read Engine DTCs.

Did the DTC reset?

Yes
Go To 3

No
Go To 11



3. CHECKING FOR GOVERNOR PRESSURE ABOVE 6 PSI

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Start the engine.

CAUTION: Apply the parking brake.


Warm the transmission to a normal operating temperature above 43° C (110° F).

CAUTION: Firmly apply the brakes.


With the engine RPM at idle, place the gear selector in Drive .
With the scan tool, read the governor pressure.

Is the governor pressure above 41.4 kPa (6 psi)?

Yes
Go To 4

No
Go To 11



4. GOVERNOR PRESSURE MATCH GAUGE PRESSURE

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Turn the ignition off to the lock position.
Install a 700 kPa (100 psi) pressure gauge to the Governor Pressure Test Port. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE - DIAGNOSIS AND TESTING)
Start the engine.
Warm the transmission to a normal operating temperature above 43° C (110° F).

CAUTION: Firmly apply the brakes.


With the engine RPM at idle, place the gear selector in Drive.
With the scan tool, read the governor pressure and compare the scan tool reading to the pressure gauge reading.

Does the scan tool Governor Pressure reading match the pressure gauge reading within 6.9 kPa (1 psi)?

Yes
Go To 5

No
Go To 8



5. CHECK FOR BURNT TRANSMISSION FLUID AND/OR EXCESSIVE DEBRIS IN THE TRANSMISSION OIL PAN

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Turn the ignition off to the lock position.
Remove the transmission oil pan per the Service Information and inspect for burnt transmission fluid and excessive debris. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE/FLUID - STANDARD PROCEDURE)

Is the transmission fluid burnt or does the transmission oil pan contain excessive debris?

Yes
Repair internal transmission as necessary. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)

No
Go To 6



6. REPLACE THE GOVERNOR PRESSURE SOLENOID AND CHECK THE VALVE BODY

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Replace the Governor Pressure Solenoid per with the Service Information. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE/GOVERNOR PRESSURE SENSOR - REMOVAL)
Start the engine.
Warm the transmission to a normal operating temperature above 43° C (110° F).

CAUTION: Firmly apply the brakes.


With the engine RPM at idle, place the gear selector in Drive.
Read the governor pressure on the pressure gauge.

Is the governor pressure on the pressure gauge above 41.4 kPa (6 psi) with the engine RPM at idle and the gear selector in Drive?

Yes
Replace the Valve Body per the Service Information. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE/VALVE BODY - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)

No
Go To 7



7. ENGINE CONTROL MODULE

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Turn the ignition off to the lock position.
Remove pressure gauge from transmission.
Install the Transmission Oil Pan and refill the transmission fluid per the service information. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE/FLUID - STANDARD PROCEDURE)
With the scan tool, erase Engine DTCs.
Test drive the vehicle.
Be sure to stop the vehicle, with the vehicle in drive on six separate occurrences for at least 6 seconds each stop.
With the scan tool, read Engine DTCs.

Did the P1757 DTC reset?

Yes
Using the schematics as a guide, check the Engine Control Module (ECM) pins, terminals, and connectors for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the ECM per the Service Information. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)

No
Go To 11



8. CHECK THE 5 VOLT SUPPLY CIRCUIT FOR AN OPEN

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Turn the ignition off to the lock position.
Disconnect the ECM harness connectors.
Disconnect the Transmission Solenoid Assembly harness connector.

NOTE: Check connectors - Clean/repair as necessary


Measure the resistance of the 5- volt Supply circuit between the Transmission Solenoid Assembly harness connector and the ECM harness connector.

Is the resistance below 5.0 ohms?

Yes
Go To 9

No
Repair the 5-volt Supply circuit for an open.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)



9. CHECK THE 5 VOLT SUPPLY CIRCUIT FOR AN OPEN INSIDE THE TRANSMISSION

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Reconnect the Transmission Solenoid Assembly harness connector.
Remove the transmission oil pan per the Service Information. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE/FLUID - STANDARD PROCEDURE)
Disconnect the Governor Pressure Sensor connector internal to the transmission.
Measure the resistance of the 5-volt Supply circuit between the ECM C2 harness connector and the Transmission Solenoid Assembly connector internal to the transmission..

Is the resistance below 5.0 ohms?

Yes
Go To 10

No
Repair or replace the 5-volt Supply circuit for an open internal to the transmission.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)



10. CHECK THE ENGINE CONTROL MODULE - 5 VOLT SUPPLY

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Reconnect the ECM harness connectors.
Ignition on, engine not running.
Measure the voltage of the 5-volt Supply circuit in the Governor Pressure Sensor connector internal to the transmission.

Is the voltage between 4.5 and 5.5 volts?

Yes
Replace the Governor Pressure Sensor per the Service Information. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE/GOVERNOR PRESSURE SENSOR - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)

No
Using the schematics as a guide, check the Engine Control Module (ECM) pins, terminals, and connectors for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the ECM per the Service Information. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/TRANSMISSION CONTROL MODULE - DIAGNOSIS AND TESTING)



11. INTERMITTENT WIRING AND CONNECTORS

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The conditions necessary to set this DTC are not present at this time.
Use the Freeze Frame Data to help duplicate the conditions in which the DTC originally set. Pay particular attention to the DTC set conditions, such as, VSS, MAP, ECT, and Load
Using the schematics as a guide, visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.
Wiggle the wiring and connectors while checking for any possible open or shorted circuits.
Check for any Service Information Tune-ups or Technical Service Bulletins that may apply.

Were there any problems found?

Yes
Repair as necessary.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)

No
Test Complete.