DTC P0977 5.3L and 6.0L
Circuit Description
The 2-3 shift solenoid (SS) valve controls the fluid flow acting on the 2-3 shift valves. The solenoid is a normally-open exhaust valve. With the 1-2 SS valve, the 2-3 SS valve allows 4 different shifting combinations. The solenoid attaches to the control valve body within the transmission. The 2-3 SS valve receives voltage through the ignition voltage circuit. The transmission control module (TCM) controls the solenoid by providing the ground path on the 2-3 SS valve control circuit.
When the TCM detects a continuous short to voltage in the 2-3 shift solenoid valve control circuit, then DTC P0977 sets. DTC P0977 is a type A DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0977 2-3 Shift Solenoid (SS) Control Circuit High Voltage
Conditions for Running the DTC
| • | The system voltage is 8-18 volts. |
| • | The engine speed is 475 RPM for 5 seconds. |
Conditions for Setting the DTC
DTC P0977 sets if the TCM commands the solenoid ON and the voltage feedback remains high, B+.
Action Taken When the DTC Sets
| • | The TCM requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL). |
| • | The TCM commands maximum line pressure. |
| • | The TCM inhibits TCC engagement. |
| • | The TCM freezes transmission adaptive functions. |
| • | At the time of the first failure, the TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record. |
| • | At the time of the second failure, the ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as a Freeze Frame. |
| • | The TCM stores DTC P0977 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met. |
Conditions for Clearing the DTC
| • | The ECM turns OFF the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request. |
| • | A scan tool can clear the DTC. |
| • | The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring. |
| • | The TCM cancels the default actions when the ignition is OFF long enough in order to power down the TCM. |
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||
2 |
Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the transmission control module (TCM). Does the 2-3 Sol. CKT status parameter display OK? | -- | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | ||||||
3 |
Refer to Automatic Transmission Inline 20-Way Connector End View . Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 4 | ||||||
4 |
Refer to Automatic Transmission Inline 20-Way Connector End View . Does the resistance measure less than the specified value? | 20 ohms | Go to Step 5 | Go to Step 7 | ||||||
5 |
Does the resistance measure less than the specified value? | 20 ohms | Go to Step 8 | Go to Step 7 | ||||||
6 | Test the control circuit of the 2-3 SS valve for a short to voltage between the TCM and the AT inline 20-way connector. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 | ||||||
7 | Replace the AT internal wiring harness. Did you complete the replacement? | -- | Go to Step 10 | -- | ||||||
8 | Replace the 2-3 SS valve. Refer to Control and Shift Solenoids Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- | ||||||
9 | Replace the TCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 10 | -- | ||||||
10 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 11 | Go to Step 2 | ||||||
11 | With the scan tool, observe the stored information, capture info, and DTC Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK |
DTC P0977 4.2L
Circuit Description
The 2-3 shift solenoid (SS) valve controls the transmission fluid pressure acting on the 1-2 and 2-3 shift valves to position the valves for the appropriate gear. The 2-3 SS valve is a normally open exhaust valve located on the lower control valve body. Ignition voltage is supplied to the solenoid. The powertrain control module (PCM), commands the solenoid ON or OFF by providing a ground path. When the 2-3 SS valve is commanded ON, the PCM senses low voltage. When the 2-3 SS valve is commanded OFF, the PCM senses high voltage.
If the PCM detects a continuous short to voltage in the 2-3 SS valve circuit, then DTC P0977 sets. DTC P0977 is a type A DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0977 2-3 Shift Solenoid (SS) Control Circuit High Voltage
Conditions for Running the DTC
| • | The engine run time is greater than 5 seconds. |
| • | The PCM commands the 2-3 SS valve ON. |
Conditions for Setting the DTC
The 2-3 SS valve feedback circuit indicates a continuous short to voltage for 4.3 seconds.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL). |
| • | The PCM commands an immediate landing to 3rd gear. |
| • | The PCM commands maximum line pressure. |
| • | The PCM freezes transmission adaptive functions. |
| • | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records. |
| • | The PCM stores DTC P0977 in PCM history. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes. |
| • | A scan tool can clear the MIL/DTC. |
| • | The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring. |
| • | The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the PCM and the wiring to the transmission.
-
This step verifies that the circuit has the correct resistance.
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||
2 |
Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the powertrain control module (PCM). When 3rd or 4th gear is commanded, does the scan tool display indicate a short to voltage? | -- | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections | ||||
Is the test lamp ON? | -- | Go to Step 4 | Go to Step 5 | |||||
4 | Test the control circuit of the 2-3 SS valve for a short to voltage between the PCM and the AT inline 20-way connector. Refer to Testing for a Short to Voltage and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10 | ||||
Refer to Automatic Transmission Inline 20-Way Connector End View . Does the resistance measure within the specified range? | 20-40 ohms | Go to Step 7 | Go to Step 6 | |||||
6 |
Does the resistance measure less than the specified value? | 100 ohms | Go to Step 8 | Go to Step 9 | ||||
7 | Measure the resistance between the 2-3 SS valve control circuit and all other terminals, except the 2-3 SS valve ignition voltage circuit, of the J 44152 . Refer to Automatic Transmission Inline 20-Way Connector End View . Does the resistance measure less than the specified value? | 100 ohms | Go to Step 8 | Go to Testing for Intermittent Conditions and Poor Connections | ||||
8 | Replace the automatic transmission wiring harness. Refer to Valve Body and Pressure Switch Replacement . Did you complete the replacement? | -- | Go to Step 11 | -- | ||||
9 | Replace the 2-3 SS valve. Refer to Valve Body and Pressure Switch Replacement . Did you complete the replacement? | -- | Go to Step 11 | -- | ||||
10 | Replace the PCM. Refer to Control Module References . Did you complete the replacement? | -- | Go to Step 11 | -- | ||||
11 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 12 | Go to Step 2 | ||||
12 | With the scan tool, observe the stored information, capture info. and DTC info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK |
