Advanced Diagnostics

DTC P1860: Inhibitor Solenoid Circuit Low Voltage




General Description
The inhibitor solenoid controls the oil pressure supply to the forward clutch and the reverse brake through a reverse inhibitor valve. When the inhibitor solenoid is shifted to the R position mistakenly during forward driving at speed, it controls the solenoid to intercept the activation of the reverse brake because there is a possibility of damaging a transmission. The inhibitor solenoid is driven by a driver circuit according to the command from the powertrain control module (PCM). This driver circuit is equipped with a diagnosis function to detect and output the disconnection of load and a short circuit, and sends back a return signal to the PCM. When the return signal is inappropriate for the PCM command, the PCM detects a malfunction and a DTC is stored.




Monitor Execution, Sequence, Duration, DTC Type, OBD Status




Enable Conditions

Malfunction Threshold
The return signal is inappropriate for the turn on command to the inhibitor solenoid.

Diagnosis Details

Conditions for illuminating the indicator
When a malfunction is detected, the D indicator blinks, and the DTC and the freeze frame data are stored in the PCM memory. The MIL does not come on.

Conditions for clearing the DTC
The DTC and the freeze frame data can be cleared by using the scan tool Clear command or by disconnecting the battery.