Diagnostic procedure

WARNING: This page is about a different car, the 2005 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

NO. 21 ENGINE NOISE DIAGNOSTIC PROCEDURE

STEP	INSPECTION	RESULTS	ACTION
1	Is squeal, click or chirp sound present?	Yes	Inspect engine oil level or drive belts.
1	Is squeal, click or chirp sound present?	No	Go to the next step.
2	Is rumble or grinding noise present?	Yes	Inspect drive belts.
2	Is rumble or grinding noise present?	No	Go to the next step.
3	Is rattle noise present?	Yes	Inspect location of rattle for loose parts.
3	Is rattle noise present?	No	Go to the next step.
4	Is hissing noise present?	Yes	Inspect for following: Vacuum leakage Spark plug looseness Intake-air system leakage Variable air duct (VAD) control system operation (See VARIABLE AIR DUCT (VAD) CONTROL SYSTEM OPERATION INSPECTION .)
4	Is hissing noise present?	No	Go to the next step.
5	Is rap or roar noise present?	Yes	Inspect exhaust system for loose parts.
5	Is rap or roar noise present?	No	Go to the next step.
6	Is knocking noise present?	Yes	Go to symptom troubleshooting "NO. 11 ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE, SURGES ".
6	Is knocking noise present?	No	If noise comes from engine internal, inspect for friction gear, timing chain or MLA noise.
7	Verify test results. If okay, return to diagnostic index to service any additional symptoms. If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram PCM if later calibration is available. Retest.