Mitsubishi ISC (idle speed control/servo) Motors

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ISC motor 

ISC Info

Mitsubishi ISC motors can fail and cause unreparable failure to the ECM. Most dealerships as well as our technicians recommend replacing your ISC when the ECM engine control computer is repaired or replaced.

Symptoms of failing ISC control motor include: idle surge, failure to idle up on cold start, idle oscillation with engine idle reving up & back between approximately 900 to 1500 rpm's at idle (which should be around 850 with engine at operating temperature) or an unresponsive high or low idle. The car should compensate and idle up when the a/c compressor, power steering or when fan is running. It's likely you'll need to replace this at some point in your Mitsubishi.

We stock Tested Idle Speed Control Motors (ISC) (also called servo) for most Mitsubishi DSM cars years 1990 1999 with a 1 year warranty.

Idle Speed Control Motor Location

The ISC is on the rear side of the throttle body, on top of the engine toward the back. It has a tan plastic plug connecting to the harness (some late models are black plastic.) The other half of it (the moving part) is sticking inside the throttle body.

Location of DSM 2.0 - 4 cylinder engines with dual overhead cam

(Eclipse, Laser, Talon, Galant)

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ISC is under throttle body assembly

ISC unit is seen here plugged in

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Location on 6 cylinder engines

(Stealth, 3000GT, Diamonté, Montero)

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3.0 liter ISC is just below air intake assembly which is easily removed with a screwdriver

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Here the 3.0 liter ISC is seen plugged in

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ISC O-ring is also replaced with our ISC motors

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Replacement of ISC and ECM does not guarantee your troubles are over. Check complete ignition & electrical

systems before reinserting your ECM unit. Many times our technicians can tell by the damage on the ECM

motherboard if the ISC was likely to have caused the damage. We can also test the ISC for proper function. 

The unwritten rule with DSM Mitsubishi's is to replace ISC with ECM or between 50,000-75,000 miles, change the

engine oil and coolant every 3,000-5000 miles, change timing belt between 50,000-65,000 miles & change

cam seals and valve stem seals (DSM 1st gen) between 75,000-100,000 miles.