Ranger 2WD L4-2.3L VIN D (2001)
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Steering wheel in the center position
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EGVR and EVAPDC at zero, if the vehicle has an EGR system
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Short and long term fuel trims (less than 15)
Perform the following steps in order:
1.
Using either NGS or WDS bring up the following PIDS: IACTRIM, IACKAM2, IACKAM3.
2.
Allow vehicle to idle until the IACTRIM PID is 0.
NOTE
IACTRIM ALWAYS TRIES TO GO TO 0. WHEN MOVING TOWARDS 0, THE IACKAM2 PID SHOULD BE CHANGING. IF IACKAM3 IS
CHANGING, THEN THE AIR CONDITIONING SHOULD BE TURNED OFF.
3.
If IACKAM2 is between -0.35 and +0.35 with IACTRIM=0, then the valve is operating properly at idle. The remainder of this TSB will help
diagnose true root cause.
4.
If IACKAM2 is not between -0.35 and +0.35, it is highly likely that the engine idle system (to include the throttle body and air intake system) -is
not operating properly.
NOTE
FOR ALL VEHICLES PLEASE RECORD THE OBSERVED IAC DUTY CYCLE AND ENGINE RPM IN THE WARRANTY CLAIMS
COMMENTS FOR THIS DIAGNOSTIC.
IAC Diagnostic Service Tips - DTC 1506 (IAC Over Speed Error) and other High Idle Concerns:
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There are two primary causes of high idle:
1.
Damaged IAC valves and
2.
Vacuum leaks
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AC valves can be damaged from engine induction backfires. Many times the customer may not notice the induction backfire but will notice the
high idle afterwards. Indications of valve damage can be a shiny, almost polished appearance in the interior of the valve and a dislocated
