P1851

DTC P1851 Solenoid - Output Shorted to Power





Circuit Description
The shift solenoids are two identical, normally open electronic exhaust valves that control upshifts and downshifts in all forward gear ranges. These shift solenoids work together in a combination of ON and OFF sequences to control the line pressure and shift mechanisms (clutches, brakes).
Solenoid 1 controls the high or low of the line pressure (flow to each clutch valve) by the operation type (ON/OFF), i.e. solenoid 1 is ON, line pressure will below (87 - 116 psi (6 - 8 bar)), solenoid 1 is OFF, line pressure will be high (232 - 261 psi (16 - 18 bar)). Solenoid 2 controls the oil flow to clutch valve E or lock-up clutch valve by the ON/OFF signal.
The TCM monitors numerous inputs to determine the appropriate solenoid state combination and transaxle gear for the vehicle operating conditions.

Conditions for Setting the DTC
- Solenoid wiring shorted to power.
- No DTC P1850, P1852.
- Immediately after the above condition occurs.

Action Taken When the DTC Sets
- Hold lamp will blink. The TCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records buffer.

Conditions for Clearing the MIL/DTC
- The hold lamp 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

Steps 1-6:

- When DTC P1851 sets, the possible cause of fault could be solenoid 1.