P0935-LINE PRESSURE SENSOR CIRCUIT HIGH





For a complete wiring diagram Refer to Section 8W

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


Possible Causes
  
(T38) LINE PRESSURE SENSOR SIGNAL CIRCUIT OPEN
  
(K900) SENSOR GROUND CIRCUIT OPEN
  
(T38) LINE PRESSURE SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
  
LINE PRESSURE SENSOR
  
POWERTRAIN CONTROL MODULE
  

Always perform the 42RLE Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)



Diagnostic Test

1.CHECK TO SEE IF DTC IS CURRENT


NOTE: This counter only applies to the last DTC set.



Is the STARTS SINCE SET counter 2 or less?

Yes
  • Go To 2


No
  • Go To 6

2.CHECK THE PCM AND WIRING



CAUTION: Removal of the Starter Relay will prevent the vehicle from being started in gear.


WARNING: The Starter Relay must be removed from the PDC. Failure to do so can result in personal injury or death.


NOTE: Removal of the Starter Relay is to prevent a Transmission, NO RESPONSE, condition and disable the starter.






NOTE: All three scan tool Line Pressure readings should be steady and ± 14 kPa or 2.0 psi of the reading specified on the Transmission Simulator.



Did the Line Pressure read within ± 14 kPa or 2.0 psi in all three positions?

Yes


No
  • Go To 3

3.CHECK THE (K900) SENSOR GROUND CIRCUIT FOR AN OPEN






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.




Is the resistance above 5.0 ohms?

Yes


No
  • Go To 4

4.CHECK THE (T38) LINE PRESSURE SENSOR SIGNAL CIRCUIT FOR AN OPEN






Is the resistance above 5.0 ohms?

Yes


No
  • Go To 5

5.CHECK THE (T38) LINE PRESSURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE








Is the voltage above 5.5 volts?

Yes


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. If no problems are found, replace and program the PCM per the Service Information. With the scan tool, perform QUICK LEARN.
  • Perform 42RLE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)

6.CHECK WIRING AND CONNECTORS






Where there any problems found?

Yes


No
  • Test Complete.