Fast Idle

FAST IDLE DESCRIPTION

5	FAST IDLE
DESCRIPTION	Engine speed continues at fast idle after engine warm-up

DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY ENGINE OPERATES AT NORMAL OPERATING TEMPERATURE NOTE: If vehicle runs normally after the ignition key is turned off, check for damaged ignition switch, IGN RUN circuit short to power, VPWR circuit short to power, etc. The ECT/CHT PID at normal operating temperature should read between 112°C (234°F) and 73°C (163°F). Does engine appear to be either overheating or not reaching normal operating temperature?	Yes	See SYMPTOM TROUBLESHOOTING CHART - ENGINE COOLING SYSTEM .
1		No	Go to next step.
2	PRELIMINARY CHECKS Perform the following preliminary checks: Vacuum leaks. Throttle plate and linkage. Cruise control linkage binding/sticking. Intake air tube (leaks). Proper sealing of intake manifold and components attached to intake air (such as the EGR valve or IAC valve). Are all checks OK?	Yes	Go to next step.
2		No	Service as necessary. Verify symptom no longer exists.
3	PERFORM PCM QUICK TEST See PCM QUICK TEST . Are any DTCs displayed during Continuous Memory, Key On Engine Off (KOEO) or Key On Engine Running (KOER) Self-Tests?	Yes	Check for cause. See DIAGNOSTIC TROUBLE CODE (DTC) INDEX - POWERTRAIN CONTROL MODULE (PCM) .
3		No	Go to next step.
4	CHECK THROTTLE POSITION (TP) SENSOR Key ON, Engine OFF (KOEO). Monitor TP PID while wiggling TP sensor circuits. Is TP V PID changing below the minimum 0.53 volts or above the maximum 1.27 volts?	Yes	Possible TP sensor concern. Go to step 2 of THROTTLE POSITION (TP) SENSOR CIRCUIT MALFUNCTION .
4		No	Go to next step.
5	CHECK FOR BASE ENGINE AIR LEAKS Check for base engine air leaks (such as intake manifold gasket air leaks). See ENGINE . Is a fault indicated?	Yes	Service as required.
5		No	Go to next step.
6	Verify test results. If OK DIAGNOSTIC INDEX to service any additional symptoms.