Diagnostic Instructions
DTC Descriptors
DTC P0973 : 1-2 Shift Solenoid (SS) Control Circuit Low Voltage
DTC P0974: 1-2 Shift Solenoid (SS) Control Circuit High Voltage
Diagnostic Fault Information
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
|
Shift Solenoid (SS) A Control
| P0973
| P0973
| P0974
|
Circuit/System Description
The 1-2 shift solenoid (SS) valve, 2-3 SS valve and the 4-5 SS valve control transmission fluid pressure acting on the shift valves to position the valves for the appropriate gear. The 1-2 SS,
2-3 SS and the 4-5 SS valves are located on the control valve body. The transmission control module (TCM) commands the solenoid ON or OFF by switching the ground path. The TCM provides voltage to the solenoid through high side
driver 2 (HSD2). When the 1-2 SS valve, 2-3 SS or the 4-5 SS valve is commanded ON, the TCM senses low voltage. When the 1-2 SS valve, 2-3 SS or the 4-5 SS valve is commanded
OFF, the TCM senses high voltage. The torque converter clutch pulse width modulated (TCC PWM) solenoid valve is a solenoid used to control the application and release of the converter clutch. The TCM provides voltage to the TCC PWM solenoid
valve through HSD2. When the solenoid is commanded OFF, the TCM senses high voltage. When the solenoid is commanded ON, the TCM senses low voltage.
Conditions for Running the DTC
| • | The engine run time is greater than 5 seconds. |
Conditions for Setting the DTC
P0973
The following conditions occur for 4.3 seconds:
| • | The TCM detects an open in the 1-2 shift solenoid valve circuit when HSD2 is commanded ON. |
| • | The TCM detects a short to ground in the 1-2 shift solenoid valve circuit when HSD2 is commanded OFF. |
P0974
The TCM detects a short to voltage in the 1-2 shift solenoid valve circuit for 4.3 seconds.
Action Taken When the DTC Sets
P0973
| • | DTC P0973 is a Type B DTC. |
| • | Powertrain braking is disabled at the time that the TCM first detects the failure, before the DTC sets. |
| • | The TCM turns off power to all solenoids. |
| • | The transmission will operate in fifth gear if the vehicle has successfully completed a 1-2 upshift in the current ignition cycle. If the vehicle has not completed a 1-2 upshift in the current ignition cycle, the transmission
will operate in fourth gear. |
| • | The TCM commands maximum line pressure. |
| • | The TCM freezes transmission adaptive functions. |
| • | The TCM inhibits TAP shift. |
P0974
| • | DTC P0974 is a Type B DTC. |
| • | Powertrain braking is disabled at the time that the TCM first detects the failure, before the DTC sets. |
| • | The TCM commands HSD1 OFF. |
| • | The TCM inhibits 3-2 downshifts if the vehicle speed is 8 km/h (5 mph) or greater. |
| • | The TCM commands maximum line pressure. |
| • | The TCM freezes transmission adaptive functions. |
| • | The TCM inhibits TAP shift. |
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
Component Connector End Views
Description and Operation
Transmission General Description
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 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
Important: Additional DTCs may set when disconnecting the automatic transmission inline 20-way connector.
- Ignition OFF, disconnect the automatic transmission (AT) inline 20-way connector at the transmission.
- Install the
J 45681
on the engine side of the AT inline 20-way connector.
- Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 17 and ground.
| ⇒ | 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. |
- Connect a test lamp between the control circuit terminal 14 and the ignition circuit terminal 17.
- 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 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. |
- If all circuits test normal, test the automatic transmission internal wiring harness and the 1-2 shift solenoid.
Component Testing
- Ignition OFF, disconnect the AT inline 20-way connector at the transmission.
- Install the
J 45681
on the transmission side of the AT inline 20-way connector.
- Test for 19-31 ohms of resistance between the control terminal 14 and the ignition terminal 17 of the transmission.
| ⇒ | 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. |
- Test for infinite resistance between each terminal and the transmission housing/case.
| ⇒ | 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.
