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 35: Idle Speed Error (2.5L): Notes
Code 35 will set when closed throttle engine speed is 150 RPM greater or less than correct idle speed for 20 seconds.
Test Number 1) IAC tester is used to extend and retract IAC valve. Movement is verified by changing engine speed. If no engine speed change occurs, valve can be retested when removed from throttle body.
Test Number 2) Checks IAC movement quality from step 1). Between 700-1500 RPM, engine speed should change smoothly with each tester light flash while extending or retracting. If IAC valve is retracted beyond control range (about 1500 RPM), it may take many flashes in the extend position before engine speed reduces. This is normal on some engines. Fully extending the IAC may cause engine to stall. This may be normal.
Test Number 3) Steps 1) and 2) verified proper IAC valve operation. This step checks IAC circuits. Each light on the node light should flash Red and Green, while the IAC valve is cycled. While the color sequence is not important, if either light is off or does not flash Red and Green, check circuits beginning with poor terminal contacts.
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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.