2.5L & 4.0L
NOTE:
On Wrangler 2.5L, manufacturer indicates engine may be equipped with a Closed Crankcase Ventilation (CCV) system or a Positive Crankcase Ventilation (PCV) system. If engine is equipped with a CCV system, it will not have a PCV valve. For more information on PCV system and CCV system, see EMISSION SYSTEMS & SUB-SYSTEMS in THEORY & OPERATION article. If engine is equipped with a PCV system, go to 4.7L WITH 45RFE TRANSMISSION
. If engine is equipped with CCV system, continue with the following procedure.
The following procedure checks throttle body calibrations for correct idle conditions. To perform the following procedure, a Fixed Orifice Adapter (6714) must be used. Procedure should only be used to diagnose the throttle body for conditions that may cause idle problems. Before performing this test, ensure Idle Air Control (IAC) motor is functioning properly. See CHECKING IDLE AIR CONTROL MOTOR .
- Turn ignition off. Remove air duct and air cleaner resonator from top of throttle body. On 2.5L, disconnect tube from fixed orifice fitting at left front side of valve cover. See Figure . Insert either end of fixed orifice adapter into disconnected tube. See Fig 1 . Go to step 3 .
- On 4.0L, disconnect rear breather tube at intake manifold fitting. See Figure . Allow breather tube to hang disconnected on side of engine. Connect a short piece of rubber hose to either end of fixed orifice adapter. See Fig 1 . Go to next step.
- On all models, connect scan tool to Data Link Connector (DLC). DLC is located below instrument panel, near steering column. Start engine and allow it to reach normal operation temperature. Turn all accessories off. Using scan tool, perform MINIMUM AIR FLOW test.
- Scan tool will count down to stabilize idle RPM and display minimum airflow RPM. If idle RPM displayed is not 500-900 RPM, replace throttle body. If idle RPM displayed is 500-900 RPM, minimum airflow is okay. Test is complete.