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Code 35: Idle Speed Error: Notes

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Code 35 will set if engine speed is 300 RPM less than or greater than desired (commanded) engine idle speed for 50 seconds.

NOTE: Test numbers refer to test numbers on diagnostic chart. Testing Idle Air Control (IAC) valve operation requires a "Scan" tester capable of cycling ECM output devices. Flow chart refers to the Tech 1 tester, which is manufacturer's version of this tester.
  1. The "Scan" tester RPM control mode is used to extend and retract the IAC valve. Valve should move smoothly within its commanded range. If idle is commanded too low, engine may stall. If idle speed is commanded too high, a time delay may occur before a commanded reduction in idle will occur. These are normal occurrences.
  2. Tech 1 commands ECM to control idle speed. The Red and Green indictor lights on tester should flash indicating a good circuit as the ECM issues commands. The pattern or frequency of the flashes is not important. If either light is off or does not flash, check circuits for faults, beginning with poor terminal contacts.
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