Circuit Description
The pressure control solenoid main modulation (MAIN MOD) is a normally closed (N/C) solenoid used to modulate transmission main pressure. The transmission control module (TCM) commands the solenoid ON when specific transmission and engine conditions are met. When solenoid MAIN MOD is commanded ON, hydraulic pressure is routed to the main pressure regulator valve, lowering transmission main pressure.
The TCM provides voltage to the MAIN MOD, torque converter clutch (TCC) and pressure control solenoid 1 (PCS1) through a separate solid-state device called high side driver 1 (HSD1). The TCM uses a low side driver to switch MAIN MOD ON and OFF.
DTC P0960 is a type A DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0960 Pressure Control Solenoid (PCS) Main Modulation (MAIN MOD) Circuit Open
Conditions for Running the DTC
| • | The components are powered and ignition voltage is greater than 9.0 volts and less than 18 volts. |
| • | TCM initialization is in process or engine speed is greater than 200 RPM and less than 7,500 RPM for less than 5 seconds. |
| • | The TCM must auto-detect the MAIN MOD solenoid for this test to run. |
Conditions for Setting the DTC
DTC P0960 sets when the TCM detects an open condition on the MAIN MOD circuit for greater than 2 seconds.
Action Taken When the DTC Sets
| • | The TCM illuminates the malfunction indicator lamp (MIL). |
| • | DTC P0960 is stored in TCM history. |
| • | The TCM inhibits MAIN MOD. |
Conditions for Clearing the MIL/DTC
A scan tool can clear the code from TCM history. The TCM automatically clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
| • | Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions: |
| - | A bent terminal |
| - | A backed-out terminal |
| - | A damaged terminal |
| - | Poor terminal tension |
| - | A chafed wire |
| - | A broken wire inside the insulation |
| • | When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change. |
| • | You may have to drive the vehicle in order to experience a condition. |
| • | DTC P0960, set in combination with DTC P2727 and P2761, may indicate an open in the high side driver circuit. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the command signal from the TCM.
-
This step tests the resistance value of the external harness and solenoid.
-
This step tests the resistance value of the solenoid and tests the internal wiring harness for opens.
-
This step tests the resistance value of the solenoid.
Step | Action | Value | Yes | No |
|---|---|---|---|---|
Schematic Reference: Automatic Transmission Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 |
Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data. Is voltage within the specified value? | 9-18 V | Go to Step 3 | Go to DTC P0562 for low voltage or DTC P0563 for high voltage |
Is the voltage within the specified value when solenoid MAIN MOD is commanded ON? | B+ | Go to Diagnostic Aids | Go to Step 4 | |
Is the resistance reading within the specified value? | 22.0 ohms at 20°C (68°F) | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 5 | |
Is the resistance within the specified value? | 22.0 ohms at 20°C (68°F) | Go to Step 7 | Go to Step 6 | |
Is the solenoid resistance within the specified value? | 22.0 ohms at 20°C (68°F) | Go to Step 8 | Go to Step 9 | |
7 | Test the MAIN MOD circuit between the TCM and the AT inline 20-way connector for an open condition. Refer to Testing for Continuity . Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10 |
8 | Replace the AT internal wiring harness. Refer to Wiring Harness Replacement . Did you complete the replacement? | -- | Go to Step 11 | -- |
9 | Replace the MAIN MOD solenoid. Refer to Control Valve Solenoid Replacement . Did you complete the replacement? | -- | Go to Step 11 | -- |
10 |
Important: In most cases, the TCM is not at fault. Investigate thoroughly before replacing the TCM. Replace the TCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | 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? | -- | System OK | |
