Circuit Description
The line pressure control (PC) solenoid valve (SLT) regulates solenoid modulator fluid passing through the solenoid into throttle signal pressure. The transmission control module (TCM) uses a pulse width modulated signal in order to control the signal pressure. The TCM compares various inputs in order to determine the appropriate pressure for a given load. The TCM varies the current to the line PC solenoid valve from 0.1 amps, for maximum line pressure to 1.1 amps, for minimum line pressure. An internal current monitor within the TCM provides feedback in order to determine actual line PC solenoid valve current draw.
If the TCM detects a continuous short to voltage in the line PC solenoid valve circuit, then DTC P0963 sets. DTC P0963 is a type A DTC.
Conditions for Running the DTC
The ignition voltage is 8-18 volts.
Conditions for Setting the DTC
The PC solenoid valve feedback circuit indicates a continuous short to voltage for 2 seconds or greater.
Action Taken When the DTC Sets
| • | The TCM requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL). |
| • | The TCM turns the Trans. Protection Mode ON. When the Trans. Protection Mode is ON, the following conditions occur: |
| - | The transmission will operate in 5th gear when the transmission is shifted into D or I range and 2nd gear when shifted into L range. |
| - | The line pressure is at maximum. |
| - | The torque converter clutch (TCC) is disabled. |
| - | The TCM freezes the transmission adaptive functions. |
| • | The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record. |
| • | The TCM stores DTC P0963 in TCM history. |
Conditions for Clearing the MIL/DTC
| • | The ECM turns off the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request. |
| • | A scan tool can clear the MIL/DTC. |
| • | The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring. |
| • | The TCM cancels the DTC default actions when the ignition is OFF long enough in order to power down the TCM. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step verifies the ability of the TCM to command the line PC solenoid valve.
-
This step verifies that the automatic transmission wiring harness and the line PC solenoid valve have correct resistance.
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 2.2L (L61) | ||||
Important:
Does the Line PC Sol. Actual Current reading vary from the Line PC Sol. Ref. Current reading by more than the specified amount? | 0.10 amps | Go to Step 3 | Go to Intermittent Conditions in Engine Controls - 2.2L (L61) | |||||
Does the resistance measure less than the specified value? | 3.8 ohms | Go to Step 4 | Go to Step 5 | |||||
4 | Test the high control circuit of the line PC solenoid valve and the low control of the line PC solenoid valve for being shorted together between the AT inline 14-way connector and the line PC solenoid valve. Refer to Circuit Testing in Wiring Systems. Did you find the condition? | -- | Go to Step 8 | Go to Step 9 | ||||
5 | Measure the resistance between the line PC solenoid valve low control circuit and all other circuits, except the line PC solenoid valve high control circuit, of the transmission side of the AT inline 14-way connector. Refer to Testing for Continuity in Wiring Systems. Does the resistance measure less than the specified value? | 100 ohms | Go to Step 8 | Go to Step 6 | ||||
6 | Test the high control circuit and the low control circuit of the line PC solenoid valve for a short to voltage or a short together between the AT inline 14-way connector and the TCM. Refer to Testing for Continuity in Wiring Systems. Did you find the condition? | -- | Go to Step 7 | Go to Step 10 | ||||
7 | Repair the wiring harness. Refer to Wiring Repairs in Wiring Systems. Did you complete the replacement? | -- | Go to Step 11 | -- | ||||
8 | Replace the internal automatic transmission wiring harness assembly (33). Refer to Wiring Harness Removal and Wiring Repairs in Wiring Systems. Did you complete the replacement? | -- | Go to Step 11 | -- | ||||
9 | Replace the control valve body assembly (39). Refer to Control Valve Body Replacement . Is the replacement complete? | -- | Go to Step 11 | -- | ||||
10 | Replace the TCM. Refer to Transmission Control Module Replacement . Is the replacement complete? | -- | Go to Step 11 | -- | ||||
11 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 12 | Go to Step 2 | ||||
12 | With the scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List in Engine Controls - 2.2L (L61) | System OK |
