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 |
Typical Scan Tool Data
Circuit | Normal | Short to Ground | Open/High Resistance | Short to Voltage |
|---|---|---|---|---|
Operating Conditions: Engine running, normal operating temperature Parameter Normal Range: OK | ||||
1-2 Sol. CKT Status | OK | Open/Short to GND | Open/Short to GND | Short to Volts |
2-3 Sol. CKT Status | OK | Open/Short to GND | Open/Short to GND | Short to Volts |
TCC Duty Cycle CKT Status | OK | Open/Short to GND | Open/Short to GND | Short to Volts |
Circuit/System Description
The 1-2 shift solenoid (SS) valve and the 2-3 SS valves control transmission fluid pressure acting on the shift valves to position the valves for the appropriate gear. The 1-2 SS and the 2-3 SS valves are normally-open exhaust valves located on the control valve body. A fused circuit supplies ignition voltage to the 1-2 SS valve and the 2-3 SS valve. The transmission control module (TCM) commands the solenoid ON or OFF by switching the ground path. When the 1-2 SS valve or the 2-3 SS valve is commanded ON, the TCM senses low voltage. When the 1-2 SS valve or the 2-3 SS valve is commanded OFF, the TCM senses high voltage.
Conditions for Running the DTC
The engine speed is greater than 500 RPM for 2 seconds.
Conditions for Setting the DTC
P0973
The TCM detects an open or short to ground on the 1-2 SS valve control circuit for 4.4 seconds.
P0974
The TCM detects a short to voltage on the 1-2 SS valve control circuit for 4.4 seconds.
Action Taken When the DTC Sets
P0973
| • | DTC P0973 is a Type B DTC. |
| • | The TCM inhibits 3-2 downshifts when the vehicle speed is greater than 52 km/h (32 mph). |
| • | The TCM commands maximum line pressure. |
| • | The TCM freezes transmission adaptive functions. |
P0974
| • | DTC P0974 is a Type B DTC. |
| • | The TCM 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
Electronic Component Description for Shift Solenoid Valves 1-2 and 2-3 information
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Special Tools
J 44152 Jumper Harness (20 pins)
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 automatic transmission (AT) inline 20-way connector at the transmission.
- Install the J 44152 on the engine side of the AT inline 20-way connector.
- Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal E and ground.
- Connect a test lamp between the control circuit terminal A and the ignition circuit terminal E.
- 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 internal transmission wiring harness assembly 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 automatic transmission (AT) inline 20-way connector at the transmission.
- Install the J 44152 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 E 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 wiring harness assembly, 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 wiring harness assembly, 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 |
