DTC P1779 Non Europe or N American Emissions
Circuit Description
The transaxle control module (TCM) is an electronic device which monitors inputs to control various transaxle functions including shift quality and transaxle sensors, switches, and components to process for use within its control program. Based on this input information, the TCM controls various transaxle output functions and devices.
The following information transmits between the TCM and the engine control module (ECM) through the controller area network (CAN):
| • | The engine malfunction signal |
| • | The engine speed |
| • | The engine output torque reduction signal |
| • | The engine coolant temperature |
Conditions for Setting the DTC
| • | The system voltage is too high or too low. |
| • | The TCM or ECM is defective. |
Action Taken When the DTC Sets
| • | No lamp control is required, but diagnostic information should be stored immediately when the malfunction is detected. |
| • | An adjustable value, calculated over the substitute map engine torque, such as the throttle position or engine speed |
Conditions for Clearing the DTC
Using a scan tool can clear history DTCs.
Diagnostic Aids
| • | Inspect the poor wiring harness connection for the TCM connectors and transaxle wiring connectors. |
| • | Inspect the improperly formed or damaged terminals. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Automatic Transmission? | -- | Go to Step 2 | |
2 |
Is the throttle position sensor (TPS) within the specified values? | 0-100% | Go to Diagnostic Aids | Go to Step 3 |
3 |
Is the resistance within the specified value? | 0 ohms | Go to Step 5 | Go to Step 4 |
4 | Repair the malfunctioning terminals as necessary. Did you complete the repair? | -- | System OK | -- |
5 |
Is the voltage within the specified values? | 11-14 V | Go to Step 6 | Go to Step 7 |
6 | Repair the short to power. Did you complete the repair? | -- | System OK | -- |
7 |
Is the DTC set? | -- | Go to Step 8 | Go to Step 9 |
8 | Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls-2.0L. Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Are there any DTCs that have not been diagnosed? | -- | Go to Step 2 | System OK |
DTC P1779 North American Emissions
Circuit Description
The transaxle control module (TCM) is an electronic device which monitors inputs to control various transaxle functions including shift quality and transaxle sensors, switches, and components to process for use within its control program. Based on this input information, the TCM controls various transaxle output functions and devices.
Information is transmitted between the TCM and ECM through the CAN. Information is as follows:
| • | The engine malfunction signal |
| • | The engine speed |
| • | The engine output torque reduction signal |
| • | The engine coolant temperature |
Conditions for Setting the DTC
| • | The system voltage is too high or too low. |
| • | The TCM or ECM is defective. |
Action Taken When the DTC Sets
| • | No lamp control is required, but diagnostic information should be stored immediately when the malfunction is detected. |
| • | An adjustable value, calculated over the substitute map engine torque, such as the throttle position or engine speed |
Conditions for Clearing the DTC
Using a scan tool can clear history DTCs.
Diagnostic Aids
| • | Inspect the poor wiring harness connection for the TCM connectors and transaxle wiring connectors. |
| • | Inspect the improperly formed or damaged terminals. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Automatic Transmission? | -- | Go to Step 2 | |
2 |
Is the throttle position sensor (TPS) within the specified values? | 0-100% | Go to Diagnostic Aids | Go to Step 3 |
3 |
Is the resistance within the specified value? | 0 ohms | Go to Step 5 | Go to Step 4 |
4 | Repair the malfunctioning terminals as necessary. Did you complete the repair? | -- | System OK | -- |
5 |
Is the voltage within the specified values? | 11-14 V | Go to Step 6 | Go to Step 7 |
6 | Repair the short to power on the terminals as necessary. Did you complete the repair? | -- | System OK | -- |
7 |
Is the DTC set? | -- | Go to Step 8 | Go to Step 9 |
8 | Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls-2.5L. Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Has the last test failed or is the current DTC displayed? | -- | Go to Step 1 | System OK |
