DTC P1840 Non-Europe or N. American Emissions
Circuit Description
The pressure control valves (PCS) 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 the electrical pressure regulating valves are supplied. As a result, smaller solenoid valves may be used. The PCS requires a constant input pressure.
Conditions for Setting the DTC
| • | Output voltage of the PCS 3, at ON, is 12 volts. |
| • | No DTC P1839, P1841. |
| • | Immediately after the above condition occurs |
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 ignition OFF/ON: 3rd gear by hydraulic control. Possible P, R and N also possible. |
| • | Power supply 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 the PCS3 valve.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Perform the Diagnostic System Check. Is the check complete? | -- | 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. Is the repair complete? | -- | System OK | -- |
5 | Replace the PCS 3. Is the replacement complete? | -- | Go to Step 6 | -- |
6 | Inspect if any DTCs are set. Are any DTCs displayed that have not been diagnosed? | -- | System OK |
DTC P1840 European and N. American Emissions
Circuit Description
The pressure control valves (PCS) 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 the electrical pressure regulating valves are supplied. As a result, smaller solenoid valves may be used. The PCS requires a constant input pressure.
Conditions for Setting the DTC
| • | Output voltage of the PCS 3 (at ON) is 12 volts. |
| • | No DTC P1839, P1841. |
| • | Immediately after the above condition occurs |
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will illuminate. |
| • | The 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 ignition OFF/ON : 3rd gear by hydraulic control. Possible P, R, and N also possible. |
| • | Power supply 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 the PCS3 valve.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Perform the Diagnostic System Check. Is the check complete? | -- | 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. Is the repair complete? | -- | System OK | -- |
5 | Replace the PCS 3. Is the replacement complete? | -- | Go to Step 6 | -- |
6 | Inspect if any DTCs are set. Are any DTCs displayed that have not been diagnosed? | -- | System OK |
