P0933
P0933-HYDRAULIC PRESSURE SENSOR RANGE/PERFORMANCE
For a complete wiring diagram, refer to the Wiring Information
Theory of Operation
Line pressure is electronically controlled by the Transmission Control System and is measured by the Line Pressure Sensor (LPS). The desired line pressure is continuously being compared to the actual line pressure and is regulated by electronically changing the duty cycle of the Pressure Control Solenoid (PCS). (5% duty cycle = solenoid off = max line pressure, 62% duty cycle = solenoid on = min line pressure).
The Transmission Control System calculates the desired line pressure based on inputs from the transmission and engine. A calculated torque input to the transmission is used as the primary input of the desired line pressure calculation and is called Torque Based Line Pressure. In addition, the line pressure is set to a preset level 1034 to 1103 kPa (150 to 160 psi) during shifts to ensure consistent shift quality.
- When Monitored:
Continuously with the ignition on, engine running, with the transmission in gear.
- Set Condition:
The PCM continuously monitors (actual) Line Pressure and compares it to Desired (target) Line Pressure. If the Line Pressure reading is more than 172.4 kPa (25 psi) higher than the Desired Line Pressure, but is less than the highest Line Pressure ever used in the current gear, the DTC sets.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Testing and Inspection
1. CHECK FOR RELATED DTCS
1. With the scan tool, read DTCs.
Are there any other line pressure DTCs present?
Yes
- Refer to DTC Based Diagnostics and perform the appropriate diagnostic procedure. Perform the test for P0934 and/or P0935 first if they are present. [1][2]P0934
No
- Go To 2
2. COMPARE ACTUAL LINE PRESSURE TO DESIRED LINE PRESSURE
CAUTION: Apply Parking Brake
1. Start the engine.
CAUTION: Firmly apply the brakes.
2. With the scan tool, monitor the Line Pressure, Desired Line Pressure and the TPS degrees.
3. While firmly applying the brakes, place the shifter in reverse, then slowly press the accelerator pedal to a TPS degree of 15°.
4. Compare the Line Pressure reading to the Desired Line Pressure reading on the scan tool.
Does the Line Pressure stay within ± 34 kPa (5 psi) of the Desired Line Pressure?
No
- Go To 3
Yes
- Go To 6
3. CHECK LINE PRESSURE CONNECTOR AND WIRING
1. Ignition on, engine not running.
2. With the scan tool, monitor the Line Pressure Sensor voltage while wiggling the wiring harness and connectors pertaining to the Line Pressure Sensor and the Transmission Solenoid/TRS Assembly.
Did the voltage remain steady while wiggling the wiring harness and connectors?
Yes
- Go To 4
No
- Disconnect and properly reconnect the Line Pressure Sensor connector. Inspect terminals and repair as necessary.
- Perform 68RFE TRANSMISSION VERIFICATION TEST. 68RFE Transmission Verification Test
4. CHECK PCM AND WIRING USING THE TRANSMISSION SIMULATOR
1. Turn the ignition off to the lock position.
2. Remove the Ignition Switch Feed fuse from the TIPM.
CAUTION: Removal of the Ignition Switch Feed fuse from the TIPM will prevent the vehicle from being started in gear.
WARNING: The Ignition Switch Feed fuse must be removed from the TIPM. Failure to do so can result in possible serious or fatal injury.
3. Install the Transmission Simulator, Miller tool #8333.
4. With the Transmission Simulator select the "OFF" position on the "Input/Output Speed" switch.
5. Ignition on, engine not running.
6. With the scan tool, monitor the Line Pressure during the following step.
7. With the Transmission Simulator, turn the selector switch to each of the 3 Line Pressure positions.
NOTE: All three scan tool Line Pressure readings should be steady and ±14 kPa (2.0 psi) or 0.1 volts of the reading specified on the Transmission Simulator.
Does the Line Pressure on the scan tool fluctuate up and down more than 69 kPa (10 psi) or 0.25 volts at any of the 3 line pressure positions on the Transmission Simulator?
Yes
- Using the schematics as a guide, check the Powertrain Control Module (PCM) terminals 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 PCM. With the scan tool, perform Quick Learn. Programming and Relearning
- Perform 68RFE TRANSMISSION VERIFICATION TEST. 68RFE Transmission Verification Test
No
- Go To 5
5. CHECK THE LINE PRESSURE SENSOR
1. Turn the ignition off to the lock position.
2. Disconnect the Transmission Simulator, Miller tool #8333 and reconnect all previously disconnected connectors.
3. Install the Line Pressure Adaptor, Miller tool #8259, and the Pressure Gauge, Miller tool #C-3293, 0 to 2000 kPa (0 to 300 psi).
4. Start the engine in park.
5. Monitor the line pressure readings of both the scan tool and the pressure gauge and compare the two readings.
Is the line pressure gauge reading within 34 kPa (5 psi) of the scan tool reading?
Yes
- Repair internal transmission and inspect the oil pump and replace if necessary. If no problems are found, replace the Transmission Solenoid/TRS Assembly - possible cause is the Pressure Control Solenoid is stuck.
- Perform 68RFE TRANSMISSION VERIFICATION TEST. 68RFE Transmission Verification Test
No
- Replace the Line Pressure Sensor.
- Perform 68RFE TRANSMISSION VERIFICATION TEST. 68RFE Transmission Verification Test
6. CHECK WIRING AND CONNECTORS
1. The conditions necessary to set this DTC are not present at this time.
2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
3. Wiggle the wires while checking for shorted and open circuits.
4. With the scan tool, check the Event Data to help identify the conditions in which the DTC was set.
Where there any problems found?
Yes
- Repair as necessary.
- Perform 68RFE TRANSMISSION VERIFICATION TEST. 68RFE Transmission Verification Test
No
- Test Complete.