DTC P1871 Non-Europe or N. American Emissions
Circuit Description
The pressure control 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 pressure control solenoid valves require a constant input pressure.
Conditions for Setting the DTC
| • | If the voltage applied to high side driver is higher than 6 volts with high side driver switch off status, then a fault is detected. |
| • | No DTC P1870. |
| • | 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 pressure control solenoid 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 P1871 sets, the possible cause of the fault could be the solenoid valve power supply line.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Is the amperage within the specified value? | 0-2 Amp | 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 circuit for a short to power. Is the action complete? | -- | System OK | -- |
5 |
Is the voltage within the specified value? | 11-14 V | Go to Step 6 | Go to Step 7 |
6 | Repair the circuits for a short to power. Is the action complete? | -- | System OK | -- |
7 | Replace the TCM. Refer to Transmission Control Module Replacement . Is the action complete? | -- | Go to Step 8 | -- |
8 |
Has the last test failed or is the current DTC displayed? | -- | Go to Step 2 | System OK |
DTC P1871 European and N. American Emissions
Circuit Description
The pressure control 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 pressure control solenoid valves require a constant input pressure.
Conditions for Setting the DTC
| • | If the voltage applied to high side driver is higher than 6V with high side driver switch off status, then a fault is detected. |
| • | Immediately after the above condition occurs. |
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 ignition OFF/ON : 3rd gear by hydraulic control. Possible P, R and N also possible. |
| • | Power supply cut off to the pressure control solenoid valve. |
Conditions for Clearing the MIL/DTC
| • | The MIL will turn OFF when the malfunction has not occurred after three-ignition cycle. |
| • | 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 P1871 sets, the possible cause of the fault could be the solenoid valve power supply line.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Is the amperage within the specified value? | 0-2 Amp | Go to Diagnostic Aids | Go to Step 3 |
3 |
Is the voltage within the specified value? | 11-14V | Go to Step 4 | Go to Step 5 |
4 | Repair the circuit for a short to power. Is the action complete? | -- | System OK | -- |
5 |
Is the voltage within the specified value? | 11-14V | Go to Step 6 | Go to Step 7 |
6 | Repair the circuits for a short to power. Is the action complete? | -- | System OK | -- |
7 | Replace the TCM. Refer to Transmission Control Module Replacement . Is the action complete? | -- | Go to Step 8 | -- |
8 |
Has the last test failed or is the current DTC displayed? | -- | Go to Step 2 | System OK |
