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P0980



DTC P0979 or P0980

Diagnostic Instructions

* Perform theDiagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* ReviewStrategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptor
DTC P0979
- Shift Solenoid (SS) 3 Control Circuit Low Voltage

DTC P0980
- Shift Solenoid (SS) 3 Control Circuit High Voltage




Diagnostic Fault Information






Typical Scan Tool Data






Circuit/System Description

Shift solenoid 3 (SS3) is a normally closed (N/C) solenoid that provides control main pressure to stroke shift valve 3. The transmission control module (TCM) determines the proper solenoid command logic to move shift valve 3 to attain a particular range. The TCM provides B+ to pressure control solenoid 2 (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 switch SS3 ON and OFF. Since the shift valve position is critical in determining the correct transmission range, a pressure switch located in the pressure switch manifold provides feedback to the TCM on the position of the valve.


Conditions for Running the DTC


P0979 or P0980
* Ignition is ON.
* Ignition voltage is greater than 9.0 V and less than 18 V.
* Engine speed is greater than 200 RPM and less than 7500 RPM for 5 seconds.



Conditions for Setting the DTC

P0979

This DTC sets when the TCM detects a short to ground or an open circuit on the SS3 control circuit for greater than 1 second.

P0980

This DTC sets when the TCM detects a short to voltage on the SS3 circuit for greater than 1 second.


Action Taken When the DTC Sets


P0979 or P0980
* The TCM requests the 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 P0979 or P0980 is stored in TCM history.
* Main modulation (MAIN MOD) is inhibited.
* The TCM freezes shift adapts.
* The TCM inhibits torque converter clutch (TCC) engagement.



Conditions for Clearing the DTC

DTCs P0979 and P0980 are Type A DTCs.


Diagnostic Aids


P0979
* You may have to drive the vehicle in order to experience a condition.
* DTC P0979, set in combination with DTCs P0964 and P0975, may indicate an open in the HSD2 circuit.


P0980

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


Reference Information
Schematic Reference

Automatic Transmission Controls Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

* Transmission General Description (Transmission General Description)
* Transmission Component and System Description (Transmission Component and System Description)
* Electronic Component Description (Electronic Component Description)

Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

1. Ignition ON, engine OFF, command the Shift Solenoid 3 ON and OFF with a scan tool. Observe the operation of the Shift Solenoid 3 parameter. The Shift Solenoid 3 parameter should turn On and Off.
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, engine OFF, verify that a test lamp illuminates between the B+ circuit terminal N and ground.

• 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.

3. Connect a test lamp between the control circuit terminal C and the B+ circuit terminal N.
4. 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.

• 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.

5. Remove the transmission oil pan. Refer to Oil Pan Replacement (Service and Repair) .
6. Test the transmission internal SS3, B+, and control circuits for a short to voltage, short to ground, or an open/high resistance.

• If the circuits test normal, test or replace the SS3 solenoid.




Component Testing


Static Testing


Note

You must perform the Circuit/System Testing first.

1. Ignition OFF, remove the SS3 from the valve body. Refer to Control Valve Solenoid Replacement (SS1, SS2, SS3, TCC, and MAIN MOD) (Control Valve Solenoid Replacement (SS1, SS2, SS3, TCC, and MAIN MOD))Control Valve Solenoid Replacement (PCS1 and PCS2) (Control Valve Solenoid Replacement (PCS1 and PCS2)) .
2. Test for resistance between the control circuit terminal B and the B+ circuit terminal A of the SS3. Refer to Temperature Versus Resistance (Transmission Fluid Temperature Sensor) (Temperature Versus Resistance (Transmission Fluid Temperature Sensor))Temperature Versus Resistance (Speed Sensor) (Temperature Versus Resistance (Speed Sensor))Temperature Versus Resistance (Solenoid) (Temperature Versus Resistance (Solenoid)) .

• If not within the specified range, replace the SS3.




Repair Instructions

Perform theDiagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Wiring Harness Replacement (Service and Repair)
* Control Valve Solenoid Replacement (SS1, SS2, SS3, TCC, and MAIN MOD) (Control Valve Solenoid Replacement (SS1, SS2, SS3, TCC, and MAIN MOD))Control Valve Solenoid Replacement (PCS1 and PCS2) (Control Valve Solenoid Replacement (PCS1 and PCS2))
* Control Module References (Programming and Relearning) for TCM replacement, setup, and programming



Repair Verification

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

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