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 Descriptor

DTC P2669: Actuator Supply Voltage 2 Open

DTC P2670: Solenoid High Control Circuit Group 2 Low Voltage

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

HSD2 B+

P2670

P2669

P2671

--

Circuit/System Description

The TCM provides B+ to shift solenoid 1 (SS1), shift solenoid 2 (SS2), shift solenoid 3 (SS3), and pressure control solenoid 2 (PCS2) through a separate solid state device called high side driver 2 (HSD2). The TCM uses low side drivers to control the solenoids.

Conditions for Running the DTC

    • Battery voltage is greater than 9.0 V and less than 18 V.
    • Engine speed is greater than 200 RPM.
    • HSD2 is commanded ON.

Conditions for Setting the DTC

P2669

This DTC sets when the HSD2 voltage is greater than 6 V and the TCM detects an open circuit on 2 or more of the solenoids (SS1, SS2, SS3, or PCS2) connected to the HSD2.

P2670

This DTC sets when the HSD2 voltage is less than 6 V and the TCM detects a short to ground on 2 or more of the solenoids (SS1, SS2, SS3, or PCS2) connected to the HSD2.

Action Taken When the DTC Sets

P2669

    • The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL).
    • 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, the transmission will shift to third range.
    • The TCM inhibits torque converter clutch (TCC) engagement.
    • DTC P2669 is stored in TCM history.

P2670

    • The TCM requests the ECM to illuminate the MIL.
    • If fault is detected in a forward range, the transmission will shift to first, third, or fifth range.
    • When the shift selector is moved to NEUTRAL, the transmission will shift to NEUTRAL.
    • When the shift selector is moved to REVERSE, the transmission will shift to REVERSE, unless the transmission is compromised by overspeeding or direction change, then a shift to NEUTRAL is made.
    • The TCM inhibits TCC engagement.
    • DTC P2670 is stored in TCM history.

Conditions for Clearing the DTC

DTCs P2669 and P2670 are Type A DTCs.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

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 Shift Solenoid 1, Shift Solenoid 2, Shift Solenoid 3, and PC Solenoid 2 solenoid ON and OFF with a scan tool. Observe the operation of the Shift Solenoid 1, Shift Solenoid 2, Shift Solenoid 3 , and PC Sol. 2 Pressure Command parameters. The Shift Solenoid 1, Shift Solenoid 2 and Shift Solenoid 3 parameters should turn On and Off and the PC Sol. 2 Pressure Command parameter should change from 0 kPa (0 psi) to 1600 kPa (232 psi).
  2. Operate the vehicle within the Conditions for Running the DTC to verify that the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Circuit/System Testing

  1. Ignition OFF, disconnect the X175 harness connector at the transmission.
  2. Ignition ON, engine OFF. 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 A and the B+ circuit terminal N.
  5. Command the Shift Solenoid 1 ON and OFF with a scan tool and verify the Shift Solenoid 1 parameter changes from On to Off. 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. Connect a test lamp between the control circuit terminal B and the B+ circuit terminal N.
  8. Command the Shift Solenoid 2 ON and OFF with a scan tool and verify the Shift Solenoid 2 parameter changes from On to Off. The test lamp should turn ON and OFF when changing between the commanded states.
  9. 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.
  10. Connect a test lamp between the control circuit terminal C and the B+ circuit terminal N.
  11. Command the Shift Solenoid 3 ON and OFF with a scan tool and verify the Shift Solenoid 3 parameter changes from On to Off. The test lamp should turn ON and OFF when changing between the commanded states.
  12. 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.
  13. Connect a test lamp between the control circuit terminal P and the B+ circuit terminal N.
  14. Command the 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.
  15. 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.
  16. Remove the transmission oil pan. Refer to Oil Pan Replacement.
  17. Test the transmission internal HSD2 B+ and SS1, SS2, SS3, and PCS2 control circuits for a short to voltage, short to ground or an open/high resistance.
  18. If the circuits test normal, test the PCS2, SS1, SS2, and SS3 solenoids.

Component Testing

Static Testing

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

  1. Ignition OFF, remove the PCS2 from the valve body. Refer to Control Valve Solenoid Replacement.
  2. Test for the specified 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.
  4. Ignition OFF, remove the SS1, SS2 and SS3 solenoids from the valve body. Refer to Control Valve Solenoid Replacement.
  5. Test for resistance between the control circuit terminal B and the B+ circuit terminal A of SS1, SS2, and SS3. Refer to Temperature Versus Resistance.
  6. If not within the specified range, replace the affected 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.