P1871

DTC P1871: EDS Valve Power Supply Circuit Shorted to Power





Circuit Description
The pressure control valves (EDS 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 EDS require a constant input pressure.

Conditions for Setting the DTC
- If the voltage applied to high side driver is higher than the threshold (6 V) 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 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 EDS 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 fault could be EDS valve power supply line.

Troubleshooting