P0803 1-4 Upshift (Skip Shift) Solenoid Control Circuit Malfunction

P0803 points to a 1-4 upshift or skip-shift solenoid control circuit malfunction. The control circuit for the skip-shift feature is abnormal.

Code details

Generic OBD-II · P0

System: Transmission
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not disable or bypass the circuit as diagnosis; test the solenoid command path and related inputs first.

Symptoms of P0803

Harsh, delayed, or slipping shifts, or being stuck in one gear.
Check-engine light, sometimes with limp-home mode.
Flaring RPM or a shudder under load.

Common causes of P0803

Low or degraded transmission fluid.
A failing speed sensor, shift solenoid, or pressure-control circuit.
Wiring, connector, or internal hydraulic/mechanical faults.

Useful checks before replacing parts

Check skip-shift solenoid power, control circuit, connector condition, fuse feed, and harness routing near the transmission.
Compare solenoid command with actual circuit voltage and driver symptoms during the skip-shift operating window.
Review clutch switch, vehicle speed, throttle, and gear-selection inputs that control skip-shift logic.

Related OBD-II codes

These nearby transmission entries can help compare wording and pin down the fault area.