Circuit Description
The pressure control (PC) solenoid valve is an electronic device that regulates transmission line pressure based on the current flow through its coil winding. The magnetic field produced by the coil moves the solenoid's internal valve which varies pressure to the pressure regulator valve. The transmission control module (TCM) controls the PC solenoid valve by applying a varying amount of amperage to the solenoid. The applied amperage can vary from 0.1-1.1 amps. Low amperage, 0.1 amp, indicates high line pressure. High amperage, 1.1 amps, indicates low line pressure. The duty cycle of the PC solenoid valve is expressed as a percentage of energized ON time. Zero percent indicates zero ON time, non-energized, or no current flow. Approximately 60 percent at idle indicates maximum ON time, energized, or high current flow. The TCM determines the appropriate line pressure for a given load by comparing the throttle position sensor voltage, the engine speed and other inputs.
When the TCM detects a continuous open or short to ground in the PC solenoid valve circuit, then DTC P0961 sets. DTC P0961 is a type C DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0961 Line Pressure Control (PC) Solenoid System Performance
Conditions for Running the DTC
| • | The system voltage is 8-18 volts. |
| • | The engine is running. |
Conditions for Setting the DTC
The PC solenoid valve duty cycle reaches its high limit, approximately 95 percent, or low limit, approximately 2 percent.
Action Taken When the DTC Sets
| • | The TCM does not request the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL). |
| • | The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM records this information as a Failure Record. |
| • | The TCM commands maximum line pressure. |
| • | The TCM freezes transmission adaptive functions. |
| • | The TCM stores DTC P0961 in TCM history. |
Conditions for Clearing the DTC
| • | The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring. |
| • | A scan tool can clear the DTC. |
Diagnostic Aids
DTC P0961 may set under low voltage conditions caused by high electrical system demands.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step tests the ability of the TCM to command the PC solenoid valve.
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This step tests the PC solenoid valve and automatic transmission (AT) wiring harness assembly for incorrect resistance.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
Important: Before clearing the DTC, use the scan tool in order to record the Failure Records. Using the Clear Info function erases the Failure Records from the transmission control module (TCM). Is the PC Sol. Actual Current always within the specified value of the PC Sol. Ref. Current? | 0.16 amp | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | |
Refer to Testing for Continuity . Refer to Automatic Transmission Inline 20-Way Connector End View . Does the resistance measure within the specified range? | 3-7 ohms | Go to Step 5 | Go to Step 4 | |
4 | Does the resistance measure greater than the specified value? | 7 ohms | Go to Step 9 | Go to Step 10 |
5 | Measure the resistance from the PC solenoid valve high control circuit of the J 44152 to the transmission case. Refer to Automatic Transmission Inline 20-Way Connector End View and Testing for Continuity . Does the resistance measure greater than the specified value? | 250 K ohms | Go to Step 6 | Go to Step 11 |
6 |
Refer to Testing for Continuity . Does the resistance measure within the specified range? | 3-7 ohms | Go to Step 8 | Go to Step 7 |
7 | Does the resistance measure greater than the specified value? | 7 ohms | Go to Step 12 | Go to Step 13 |
8 | Using the DMM and the J 35616 , measure the resistance from TCM connector the PC solenoid valve high control circuit to ground. Refer to Testing for Continuity . Does the resistance measure greater than the specified value? | 250 K ohms | Go to Step 17 | Go to Step 14 |
9 | Test the high control circuit and the low control circuit of the PC solenoid for an open between the AT inline 20-way connector and the PC solenoid. Refer to Testing for Continuity . Did you find an open condition? | -- | Go to Step 16 | Go to Step 15 |
10 | Test the high control circuit and the low control circuit of the PC solenoid for a shorted together condition between the AT inline 20-way connector and the PC solenoid. Refer to Circuit Testing . Did you find a shorted together condition? | -- | Go to Step 16 | Go to Step 15 |
11 | Test the high control circuit and the low control circuit of the PC solenoid for a short to ground between the AT inline 20-way connector and the PC solenoid. Refer to Testing for Short to Ground . Did you find a short to ground condition? | -- | Go to Step 16 | Go to Step 15 |
12 | Test the high control circuit and the low control circuit of the PC solenoid for an open between the TCM and the AT inline 20-way connector. Refer to Testing for Continuity and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 19 | -- |
13 | Test the high control circuit and the low control circuit of the PC solenoid for a shorted together condition between the TCM and the AT inline 20-way connector. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 19 | -- |
14 | Test the high control circuit and the low control circuit of the PC solenoid for a short to ground between the TCM and the AT inline 20-way connector. Refer to Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 19 | -- |
15 | Replace the PC solenoid valve. Refer to Valve Body and Pressure Switch Replacement . Did you complete the replacement? | -- | Go to Step 19 | -- |
16 | Replace the AT wiring harness. Refer to Valve Body and Pressure Switch Replacement . Did you complete the replacement? | -- | Go to Step 19 | -- |
17 | Test the high control circuit and the low control circuit of the PC solenoid for a short to voltage. Refer to Testing for a Short to Voltage and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 18 |
18 | Replace the TCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 19 | -- |
19 | Perform the following procedure in order to verify the repair:
The difference between the scan tool PC Sol. Actual Current and the PC Sol. Ref. Current is less than 0.16 amp. Has the test run and passed? | -- | Go to Step 20 | Go to Step 2 |
20 | 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? | -- | System OK |
