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 P0973 : 1-2 Shift Solenoid (SS) Control Circuit Low VoltageDTC P0974: 1-2 Shift Solenoid (SS) Control Circuit High Voltage
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage |
|---|---|---|---|
Ignition 1 Voltage | P0973, P0976, P2764 | P0973, P0976, P2764 | -- |
1-2 SS Valve Control | P0973 | P0973 | P0974 |
2-3 SS Valve Control | P0976 | P0976 | P0977 |
TCC PWM Valve Control | P2764 | P2764 | P2763 |
Circuit/System Description
The 1-2 shift solenoid (SS) valve controls the fluid flow acting on the 1-2 and 3-4 shift valves. The solenoid is a normally-open exhaust valve. With the 2-3 SS valve, the 1-2 SS valve allows 4 different shifting combinations. The solenoid attaches to the control valve body within the transmission. The 1-2 SS valve receives ignition voltage through the ignition voltage circuit. The transmission control module (TCM) controls the solenoid by providing the ground path on the 1-2 SS valve control circuit.
Conditions for Running the DTC
| • | The engine speed is 500 RPM for 5 seconds. |
| • | The 1-2 SS is commanded ON. |
Conditions for Setting the DTC
P0973
Either one of the following conditions occurs for 4.3 seconds:
| • | The TCM detects an open in the 1-2 shift solenoid valve circuit when commanded ON. |
| • | The TCM detects a short to ground in the 1-2 shift solenoid valve circuit when commanded ON. |
P0974
If the TCM commands the solenoid ON and the voltage feedback remains high B+.
Action Taken When the DTC Sets
P0973
| • | P0973 is a Type B DTC. |
| • | The TCC commands maximum line pressure. |
| • | The TCM inhibits 3-2 shift until vehicle speed is less than 20 km/h (12 mph). |
| • | The TCM freezes transmission adaptive functions. |
P0974
| • | The TCC commands maximum line pressure. |
| • | The TCM freezes transmission adaptive functions. |
Conditions for Clearing the DTC
DTCs P0973 and P0974 are Type B DTCs.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Description and Operation
Transmission General Information
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Transmission Control Module Scan Tool Information
Special Tools
| • | J 44152 Jumper Harness (20 Pins) |
| • | J 45681 Jumper Harness |
Circuit/System Verification
- Ignition ON, engine OFF, observe the 1-2 Sol. CKT Status parameter while commanding the 1-2 SS ON and OFF with a scan tool. The reading should display OK or Indeterminate.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
- Ignition OFF, disconnect the AT inline 20-way connector at the transmission.
- Install the J 45681 jumper harness, on the engine side of the AT inline 20-way connector.
- Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal L and ground.
- Connect a test lamp between the control circuit terminal A and the ignition circuit terminal L.
- Command the 1-2 SS ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, test the automatic transmission internal wiring harness and the 1-2 shift solenoid.
Important: Additional DTCs may set when disconnecting the automatic transmission inline 20-way connector.
| ⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all components connected to the ignition circuit and replace as necessary. |
| ⇒ | 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. |
Component Testing
- Ignition OFF, disconnect the AT inline 20-way connector at the transmission.
- Install the J 44152 jumper harness (20 pins), on the transmission side of the AT inline 20-way connector.
- Test for 19-31 ohms of resistance between the control terminal A and the ignition terminal L of the transmission.
- Test for infinite resistance between each terminal and the transmission housing/case.
| ⇒ | If not within the specified range, test the circuits for a short to ground or an open/high resistance. If a circuit is shorted or open replace the internal transmission harness, if the circuits test normal, replace the 1-2 shift solenoid. |
| ⇒ | If not the specified value, test the circuits for a short to ground or an open/high resistance. If a circuit is shorted replace the internal transmission harness, if the circuits test normal, replace the 1-2 shift solenoid. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
| • | Control Module References for TCM replacement, setup and reprogramming |
