Turn ignition on, engine not running. With the DRBIII®, read DTCs and record related Freeze Frame data. Is the Good Trip counter displayed and equal to zero? If yes, go to next step. If no, go to step 6.
Turn the ignition off. Remove the IAC Motor. Inspect the IAC Motor and passages way for any obstructions or damage to motor. Were any problems found? If yes, repair as necessary. If no, go to next step.
Start the engine. Inspect the vehicle for external vacuum leaks. Inspect the engine for internal vacuum leaks. Were any vacuum leaks found? If yes, repair the vacuum leak as necessary. If no, go to next step.
Inspect the Air Induction System for dirty air cleaner, foreign material trapped in the air intake tube, etc. Also check for leaks in the air intake tube connection, air cleaner housing, etc. Were any problems found? If yes, repair or replace as necessary. If no, go to next step.
Inspect the throttle body plate carbon build-up or other restrictions. Inspect the throttle linkage for binding and smooth operation. Ensure the throttle plate is resting on the stop at idle. Were any problems found? If yes, repair or replace as necessary. If no, test is complete.

WARNING: When the engine is operating, do not stand in a direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing.

The conditions that set the DTC are not present at this time. The following may help in identifying the intermittent condition. With the engine running at normal operating temperature, monitor the DRBIII® parameters related to the DTC while wiggling the wiring harness. Look for parameter values to change and/or a DTC to set. Review the DRBIII® Freeze Frame information. If possible, try to duplicate the conditions under which the DTC was set. Refer to any Technical Service Bulletins (TSB) that may apply. Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals. Were any of the above conditions present? If yes, repair as necessary. If no, test is complete.

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.

Safety Warning

DTC P0519: Idle Speed Performance: Testing

Use the Manual With the Right Hardware

When to See a Mechanic

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