P1762

P1762-GOV PRESS SENSOR OFFSET VOLTS TOO LOW OR HIGH (DIESEL)





For a complete wiring diagram refer to Diagrams/Electrical. Electrical Diagrams


Theory of Operation


The Governor Pressure Sensors output is used as a control input to the Governor Pressure Control System. The Governor Pressure Control System is used to regulate the governor pressure which controls the shifts for first, second, and third gear.


- When Monitored:

While the engine is running and the vehicle gear selector is in park or neutral for more than 3.0 seconds with the throttle position less than 10%.

- Set Condition:

This DTC will set if the Governor Pressure is greater than 3 psi while the vehicle is in Park 3 times in a drive cycle.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Checkout (Diesel)



Diagnostic Test


1. OTHER TRANSMISSION DTCS PRESENT

Ignition on, engine not running.

With the scan tool, read Engine DTCs.

Are any other transmission DTCs present?

Yes

- Refer to the Transmission category and perform the appropriate symptom(s).

No

- Go To 2



2. CHECK IF THE GOVERNOR PRESSURE IS ABOVE 21 KPA (3 PSI) IN PARK


CAUTION: Apply the parking brake.

Start the engine and allow the engine to idle.

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

With the scan tool in Sensors, read the Governor Pressure with the Transmission Shift selector in Park.

Is the Governor Pressure reading on the scan tool above 21 kPa or 3 psi?

Yes

- Go To 3

No

- Go To 10



3. COMPARE SCAN TOOL GOVERNOR PRESSURE READING TO PRESSURE GAUGE READING

Turn the ignition off to the lock position.

Connect a 700 kPa (100 psi) Pressure Gauge to the Governor Pressure test port.

Start the engine and allow the engine to idle.

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

With the scan tool, read the Governor Pressure and compare the scan tool Governor Pressure 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 4

No

- Go To 7



4. TRANSMISSION - INTERNAL DAMAGE

Turn the ignition off to the lock position.

Remove the transmission oil pan.

Inspect the transmission oil pan for burnt oil and/or excessive debris.

Does the transmission contain burnt oil and/or excessive debris?

Yes

- Repair internal transmission as necessary.
- Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). Transmission Verification Test

No

- Go To 5



5. CHECK INTERNAL TRANSMISSION FOR A FLUID LEAK

Inspect the transmission for internal fluid leakage in the Valve Body or the Governor Pressure Solenoid.

Were there any problems found?

Yes

- Repair the internal transmission as necessary.
- Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). Transmission Verification Test

No

- Go To 6



6. VERIFY OPERATION - TEST DRIVE

Remove the pressure gauge from the transmission.

Install the transmission oil pan and refill the transmission.

With the scan tool, erase Engine DTCs.

Test drive the vehicle.

Be sure to stop the vehicle and move the gear selector into the park position for a minimum of 5 seconds at least three times during the drive cycle.

With the scan tool, read Engine DTCs.

Did the 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.
- Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). Transmission Verification Test

No

- Go To 10



7. CHECK THE 5 VOLT SUPPLY CIRCUIT FOR AN OPEN





Turn the ignition off to the lock position.

Disconnect the ECM C2 harness connector.

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 C2 harness connector.

Is the resistance below 5.0 ohms?

Yes

- Go To 8

No

- Repair 5-volt Supply circuit for an open.
- Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). Transmission Verification Test



8. CHECK THE 5 VOLT SUPPLY CIRCUIT FOR AN OPEN - INTERNAL





Reconnect the Transmission Solenoid Assembly harness connector.

Remove the Transmission Oil Pan.

Disconnect the Governor Pressure Sensor harness connector internal to the transmission.


NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance of the 5-volt Supply circuit between the ECM C2 harness connector and the Governor Pressure Sensor connector internal to the transmission.

Is the resistance below 5.0 ohms?

Yes

- Go To 9

No

- Repair or replace the 5-volt Supply circuit for an open internal to the transmission.
- Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). Transmission Verification Test



9. GOVERNOR PRESSURE SENSOR





Reconnect the ECM harness connectors.


NOTE: The ECM harness connectors must be connected during this test.

Ignition on, engine not running.

Measure the voltage of the 5-volt Supply circuit at 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.
- Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). Transmission Verification Test

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.
- Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). Transmission Verification Test



10. INTERMITTENT WIRING AND CONNECTORS

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). Transmission Verification Test

No

- Test Complete.