GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P0964: Pressure Control (PC) Solenoid 2 Control Circuit Open

DTC P0966: Pressure Control (PC) Solenoid 2 Control Circuit Low Voltage

DTC P0967: Pressure Control (PC) Solenoid 2 Control Circuit High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Control

P0966

P0964

P0967

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Circuit/System Description

The Pressure Control Solenoid 2 (PCS2) is a solenoid that controls pressure which is proportional to the current. The transmission fluid pressure from PCS2 is directed to another valve which regulates the transmission fluid flow and pressure through shift valves that allows it to engage different clutches.

The transmission control module (TCM) provides B+ to PCS2 and shift solenoids 1,2, and 3 (SS1, SS2, and SS3) through a separate solid state device called high side driver 2 (HSD2). The TCM uses a low side driver to control the current flow to the PCS2. The TCM controls the current to the solenoid by changing the amount of time that the low side driver is on.

Conditions for Running the DTC

P0964, P0966, or P0967

    • No DTCs P2669, P2670, or P2671.
    • Battery voltage is greater than 9.0 V and less than 18 V.
    • Engine speed is greater than 200 RPM.
    • Engine crank time is not extended.

Conditions for Setting the DTC

P0964

This DTC sets when the TCM detects an open circuit on the PCS2 control circuit for greater than 1 second.

P0966

This DTC sets when the TCM detects a short to ground on the PCS2 control circuit for greater than 1 second.

P0967

This DTC sets when the TCM detects a short to voltage on the PCS2 circuit for greater than 1 second.

Action Taken When the DTC Sets

P0964, P0966, or P0967

    • The TCM requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL).
    • If the fault occurs while in a forward range, a shift to 1st, 3rd or 5th range is made.
    • While diagnostic response is active, if the shift selector is moved to NEUTRAL, the transmission will shift to NEUTRAL. If the shift selector is moved to REVERSE, the transmission will shift to REVERSE. If the shift selector is moved to a forward range or to REVERSE and the transmission is compromised by overspeeding or direction change, the transmission will shift to NEUTRAL.
    • DTC P0964, P0966, or P0967 is stored in TCM history.

Conditions for Clearing the DTC

DTCs P0964, P0966, and P0967 are Type A DTCs.

Diagnostic Aids

P0964

    • You may have to drive the vehicle in order to experience a condition.
    • If DTC P0964 is accompanied by DTC P0972, and/or DTC P0975, and/or DTC P0978, the open is most likely in the HSD2 circuit.

P0966 and P0967

You may have to drive the vehicle in order to experience a condition.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

    •  Transmission General Description
    •  Transmission Component and System Description
    •  Electronic Component Description

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, engine OFF, command the PC Solenoid 2 ON and OFF with a scan tool. Observe the operation of the PC Sol. 2 Pressure Command parameter. The PC Sol. 2 Pressure Command parameter should change from 1600 kpa (232 psi) to 0 kpa (0 psi).
  2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

  1. Ignition OFF, disconnect the X175 harness connector at the transmission.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal N and ground.
  3. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the TCM.
  4. Connect a test lamp between the control circuit terminal P and the B+ circuit terminal N.
  5. Ignition ON, engine OFF, command PC Solenoid 2 ON and OFF with a scan tool and verify the PC Sol. 2 Pressure Command parameter changes from 1600 kPa (232 psi) to 0 kPa (0 psi). The test lamp should turn ON and OFF when changing between the commanded states.
  6. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the TCM.
    If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the TCM.
  7. Remove the transmission oil pan. Refer to Oil Pan Replacement.
  8. Test the transmission internal B+ and control circuits for a short to voltage, short to ground, or an open/high resistance.
  9. If the circuits test normal, test or replace the PCS2 solenoid.

Component Testing

Static Testing

    Note: You must perform the Circuit/System Testing first.

  1. Ignition OFF, remove the PCS2 solenoid from the valve body. Refer to Control Valve Solenoid Replacement.
  2. Test for resistance between the control circuit terminal 2 and the B+ circuit terminal 1 of the PCS2. Refer to Temperature Versus Resistance.
  3. If not within the specified range, replace the PCS2 solenoid.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Wiring Harness Replacement
    •  Control Valve Solenoid Replacement
    •  Control Module References for TCM replacement, setup, and programming

Repair Verification

If another DTC is present, refer to Diagnostic Trouble Code (DTC) List - Vehicle and perform the appropriate diagnostic procedure.