P0935
P0935-LINE PRESSURE SENSOR CIRCUIT HIGH
For a complete wiring diagram Consult Diagrams/Electrical
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 827 to 931 kPa (120 to 135 psi) during shifts and in Park and Neutral to ensure consistent shift quality.
The monitored Line Pressure Sensor voltage should always be between 0.35 and 4.75 volts. Any monitored voltages outside these parameters indicate an Line Pressure Sensor or wiring problem and will cause either DTC P0934 or P0935 to set.
- When Monitored:
Continuously with ignition on and engine running.
- Set Condition:
This DTC will set if the monitored Line Pressure Sensor voltage is greater than or equal to 4.75 volts for the period of 0.18 seconds
Always perform the 40/41TE Pre-Diagnostic Troubleshooting procedure before proceeding. Testing and Inspection
Diagnostic Test
1. CHECK IF DTC IS CURRENT
With the scan tool, read DTCs.
Is the status Active or is the Starts Since Set counter 2 or less for this DTC?
Yes
- Go to 2
No
- Go to 6
2. CHECK THE PCM AND WIRING USING THE TRANSMISSION SIMULATOR
Turn the ignition off to the lock position.
Remove the Starter Relay.
CAUTION: Removal of the Starter Relay will prevent the vehicle from being started in gear.
WARNING: The Starter Relay must be removed. Failure to do so can result in personal injury or death.
Install the Transmission Simulator, Miller tool #8333 and the Electronic Transmission Adapter kit.
Ignition on, engine not running.
With the scan tool, monitor the Line Pressure.
Using the Transmission Simulator, set the rotary switch to each of the 3 line pressure positions.
NOTE: All three scan tool Line Pressure readings should be steady and ± 14 kPa or 2.0 psi (0.2 volts) of the reading specified on the Transmission Simulator.
Did the Line Pressure read within ± 14 kPa or 2.0 psi (0.2 volts) in all three positions?
Yes
- Replace the Line Pressure Sensor.
- PERFORM 40/41TE VERIFICATION TEST Transmission Verification Test
No
- Go to 3
3. CHECK THE (K900) SENSOR GROUND CIRCUIT FOR AN OPEN
Turn the ignition off to the lock position.
Disconnect the Transmission Simulator, Miller tool #8333 and the Electronic Transmission Adapter kit.
Disconnect the PCM C2 harness connector and connect Miller tool #8815.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller tool #8815 to perform diagnosis.
Measure the resistance of the (K900) Sensor Ground circuit between the Line Pressure Sensor/Variable Force Solenoid Assembly harness connector and the appropriate terminal of Miller tool #8815.
Is the resistance above 5.0 ohms?
Yes
- Repair the (K900) Sensor Ground circuit for an open.
- PERFORM 40/41TE VERIFICATION TEST Transmission Verification Test
No
- Go to 4
4. CHECK THE (T38) LINE PRESSURE SIGNAL CIRCUIT FOR AN OPEN
Disconnect the PCM C4 harness connector and connect Miller tool #8815.
Measure the resistance of the (T38) Line Pressure Signal circuit between the Line Pressure Sensor/Variable Force Solenoid Assembly harness connector and the appropriate terminal of Miller tool #8815.
Is the resistance above 5.0 ohms?
Yes
- Repair the (T38) Line Pressure Signal circuit for an open.
- PERFORM 40/41TE VERIFICATION TEST Transmission Verification Test
No
- Go to 5
5. CHECK THE (T38) LINE PRESSURE SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
Remove the Transmission Control Relay.
Connect a jumper wire between the Fused B(+) circuit and the Transmission Control Output circuit in the Transmission Control Relay connector.
Ignition on, engine not running.
Measure the voltage of the (T38) Line Pressure Signal circuit.
Is the voltage above 5.5 volts?
Yes
- Repair the (T38) Line Pressure Signal circuit for a short to voltage.
- PERFORM 40/41TE VERIFICATION TEST Transmission Verification Test
No
- 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. Check for any Service Bulletins that may apply. If no problems are found, replace and program the PCM. With the scan tool perform the Quick Learn procedure.
- PERFORM 40/41TE VERIFICATION TEST Transmission Verification Test
6. CHECK 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.
With the scan tool, check the Event Data to help identify the conditions in which the DTC was set.
Check for any Service Bulletins that may apply.
Where there any problems found?
Yes
- Repair as necessary.
- PERFORM 40/41TE VERIFICATION TEST Transmission Verification Test
No
- Test Complete.