P0746-LINE PRESSURE SOLENOID PERFORMANCE
For a complete wiring diagram Refer to Section 8W.
Theory of Operation
The Line Pressure Solenoid regulates the Line Pressure (Oil Pump discharge pressure) which is controlled by the Transmission Control Module (TCM). If the line pressure does not reach at the desired pressure due to driving conditions, the possibility of belt slippage can occur. The gear ratio changes to a value beyond the maximum gear ratio which is a calculation between the Primary Pulley speed and the Secondary Pulley speed. If the gear ratio exceeds a predetermined limit a DTC will set.
- When Monitored:
Ignition on, engine running with the transmission in a valid forward gear.
Vehicle speed greater than 10 Km/h (6 mph).
Accelerator Pedal Position (APP) greater than 12.5%.
Engine rpm greater than 450 rpm.
Primary Pulley Speed grater than 500 rpm.
No active DTCs from the following:
- Line Pressure Solenoid
- Temperature Sensor
- Primary or Secondary Pressure Sensor
- Transmission Range Sensor
- Step Motor
- Secondary Solenoid electrical
- Input and Output Speed Sensor
- Torque Convertor Clutch
- CAN Bus
- Over Temperature Condition
- Set Condition:
Condition one: Gear ratio is greater than 2.7 - 2 for the period of 0.2 seconds (first trip).
Condition two: Gear ratio is greater than 3.5 - 1 for the period of 0.1 seconds (second trip).
| Possible Causes |
| (T20) LINE PRESSURE SOLENOID CONTROL CIRCUIT OPEN (HIGH RESISTANCE) |
| INTERNAL TRANSMISSION |
| TRANSMISSION CONTROL MODULE |
Always perform the CVT Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)
Diagnostic Test
1. CHECK TO SEE IF THE DTC IS ACTIVEWith the scan tool, read Transmission DTCs.
Is the status Active for this DTC or is the STARTS SINCE SET counter 2 or less?
Yes
- Go To 2
No
- Go To 5
2. CHECK IF SPEED SENSOR DTCS ARE PRESENT
With the scan tool, read Transmission DTCs.
Are there any Active or Stored Speed Sensor DTCs also present?
Yes
- Refer to the CVT Electrical Diagnostics category and perform the appropriate symptom.
No
- Go To 3
3. CHECK THE (T20) LINE PRESSURE SOLENOID CONTROL CIRCUIT
Turn the ignition off to the lock position.
Disconnect the Transmission Solenoid/Pressure Switch Assembly harness connector.
Ignition on, engine not running.
With the scan tool, actuate the Line Pressure Solenoid (PL).
Using a 12-volt test light connected to ground, check the (T20) Line Pressure Solenoid Control circuit in the Transmission Solenoid/Pressure Switch Assembly harness connector.
NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly?
Yes
- Replace or repair the CV Transmission per the Service Information.
- Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)
No
- Go To 4
4. CHECK THE TRANSMISSION CONTROL MODULE
Turn the ignition off to the lock position.
Disconnect the TCM C1 harness connector.
Connect a jumper wire between the (T20) Line Pressure Solenoid Control circuit in the TCM C1 harness connector and B(+).
Using a 12-volt test light connected to ground, check the (T20) Line Pressure Solenoid Control circuit in the Transmission Solenoid/Pressure Switch Assembly harness connector.
Does the test light illuminate brightly?
Yes
- Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for any Service Bulletins for possible causes that may apply. If no problems are found, replace the TCM per the Service Information.
- Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)
No
- Repair the (T20) Line Pressure Solenoid Control circuit for an open (high resistance).
- Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)
5. INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wires while checking for shorted and open circuits.
Were there any problems found?
Yes
- Repair as necessary.
- Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)
No
- Test Complete.