DTC P1840 Non Europe or N American Emissions
Circuit Description
The pressure control solenoid (PCS) valves, valves 3, 4, 5, and 6, are precision electronic pressure regulators that control the operation of the clutches, brakes, and lock-up clutch.
The valve reduces the system pressure with which the downstream solenoid valves and electrical pressure regulating valves are supplied. It is possible to use smaller solenoid valves as a result. The PCS require a constant input pressure.
Conditions for Setting the DTC
| • | The output voltage of the PCS 3, at ON, is 12 volts. |
| • | No DTC P1839 or P1841. |
Action Taken When The DTC Sets
| • | The hold lamp will blink. |
| • | The transmission control module (TCM) will record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records buffer. |
| • | Adopt Emergency/Substitute mode and constant 4th gear by hydraulic control. |
| • | After the ignition is OFF/ON: 3rd gear by hydraulic control. Possible P, R, and N also possible. |
| • | The power supply is cut-off to the PCS valve. |
Conditions for Clearing the Hold Lamp/DTC
| • | The hold lamp will turn OFF when the malfunction has not occurred after 3 ignition cycles. |
| • | A history DTC will clear after 40 consecutive warm-up cycles without a fault. |
| • | Using a scan tool can clear history DTCs. |
Diagnostic Aids
When DTC P1840 sets, the possible cause of the fault could be PCS 3.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Automatic Transmission? | -- | Go to Step 2 | |
2 |
Does the PCS 3 change ON/OFF? | -- | Go to Diagnostic Aids | Go to Step 3 |
3 |
Is the voltage within the specified value? | 11-14 V | Go to Step 4 | Go to Step 5 |
4 | Repair the internal line, PCS 3, for a short to power. Did you complete the repair? | -- | System OK | -- |
5 | Replace the PCS 3. Did you complete the replacement? | -- | Go to Step 6 | -- |
6 | Observe if any DTCs are set. Are there any DTCs that have not been diagnosed? | -- | System OK |
DTC P1840 European and N American Emissions
Circuit Description
The pressure control solenoid (PCS) valves, valves 3, 4, 5, and 6, are precision electronic pressure regulators that control the operation of the clutches, brakes, and lock-up clutch.
The valve reduces the system pressure with which the downstream solenoid valves and electrical pressure regulating valves are supplied. It is possible to use smaller solenoid valves as a result. The PCS require a constant input pressure.
Conditions for Setting the DTC
| • | The output voltage of the PCS 3, at ON, is 12 volts. |
| • | No DTC P1839 or P1841. |
Action Taken When The DTC Sets
| • | The malfunction indicator lamp (MIL) will illuminate. |
| • | The transmission control module (TCM) will record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records buffer. |
| • | Adopt Emergency/Substitute mode and constant 4th gear by hydraulic control. |
| • | After the ignition is OFF/ON: 3rd gear by hydraulic control. Possible P, R, and N also possible. |
| • | The power supply is cut-off to the PCS valve. |
Conditions for Clearing the MIL/DTC
| • | The MIL will turn OFF when the malfunction has not occurred after 3 ignition cycles. |
| • | A history DTC will clear after 40 consecutive warm-up cycles without a fault. |
| • | Using a scan tool can clear history DTCs. |
Diagnostic Aids
When DTC P1840 sets, the possible cause of the fault could be PCS 3.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Automatic Transmission? | -- | Go to Step 2 | |
2 |
Does the PCS 3 change ON/OFF? | -- | Go to Diagnostic Aids | Go to Step 3 |
3 |
Is the voltage within the specified value? | 11-14 V | Go to Step 4 | Go to Step 5 |
4 | Repair the internal line, PCS 3, for a short to power. Did you complete the repair? | -- | System OK | -- |
5 | Replace the PCS 3. Did you complete the replacement? | -- | Go to Step 6 | -- |
6 | Observe if any DTCs are set. Are there any DTCs that have not been diagnosed? | -- | System OK |
