P0726 Engine Speed Input Circuit Range/Performance

P0726 indicates range or performance trouble in the engine speed input circuit. Engine speed data is present but implausible for transmission control.

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 assume a transmission sensor is at fault until engine speed data quality is verified.

Symptoms of P0726

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 P0726

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

Compare engine RPM with input speed, output speed, gear command, and other module RPM data during the fault condition.
Inspect crank sensor signal quality, module communication, wiring, grounds, and related engine speed or cam/crank codes.
Check whether the issue appears during cranking, idle, shifting, or high-load operation.

Related OBD-II codes

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