ZF 4HP 16 - Automatic Transmission (Non-Europe or N. American Emissions)

DTC P1866 (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 valves require a constant input pressure.

Conditions for Setting the DTC

* Output ampere of the solenoid valve 5 is less than 10 mA.
* No DTC P1864, P1865.
* 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. 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 P1866 sets, the possible cause of fault could be the pressure control valve 5.