Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Code 44, Idle Switch Circuit Open Or MISADJUSTED
This code sets if ECM sees an open switch or circuit at idle conditions. When properly adjusted, the TPS idle switch pulls ECM circuit low (to ground) when throttle is closed. If idle switch resistance is measured separately, it shows little or no resistance when closed. When throttle is opened, the circuit goes high at the ECM. If idle switch is measured separately, it shows open (infinite resistance).
- Applying vacuum to throttle opener ensures throttle is in idle position. Resistance should be 500 ohms or less at idle and infinite at wide open throttle. If TPS is misadjusted, this could keep idle switch open at closed throttle.
- TPS checked okay in step 1), this checks for an open circuit or faulty ECM.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.