Speed Control Output Circuit Continuity
The engine's cruise control system has a broken wire or bad connection preventing the ECU from controlling your vehicle's speed. Think of it like a remote control with a severed antenna—the signal can't get through.
The ECM monitors the continuity and voltage levels of the cruise control solenoid or actuator circuit. It sends a control signal and checks for proper circuit resistance and response. If the circuit is open, shorted, or the actuator won't respond, the fault is triggered.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Circuit Continuity | Complete circuit with <5 ohms resistance | Open circuit or resistance >10 ohms |
| Actuator Response Voltage | 12V control signal with proper feedback | No voltage or improper feedback signal |
Code P1574 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P1574 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.