Code 35 - Idle Speed Error: Notes

1987 Pontiac Fiero Base, AutomaticSECTION Notes

Code 35 will set if engine speed is 100 RPM less than or greater than desired (commanded) engine speed for 45 seconds.

NOTE: Test numbers refer to test numbers on diagnostic chart.
  1. Continue with test even if engine will not idle. If idle is too low, "Scan" tester will display 80 or more counts, or steps. If idle is high, it will display zero counts. Occasionally an erratic or unstable idle may occur. Engine speed may vary 200 RPM or more up and down. If this occurs, disconnect IAC. If the condition is unchanged, the IAC is not at fault (there is a system problem). Proceed to DIAGNOSTIC AIDS.
  2. When the engine was stopped, the IAC valve retracted (more air) to a fixed park position for increased airflow and idle speed during the next engine start. The "Scan" tester will display 80 or more counts.
  3. Be sure to disconnect the IAC valve prior to this test. The test light will confirm the ECM signals by a steady or flashing light on all circuits.
  4. There is a remote possibility that one of the circuits is shorted to voltage which would have been indicated by a steady light. Disconnect ECM and turn the ignition on, and probe terminals to check for this condition.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.