NOTE: This procedure uses multiple tools/methods to help locate the source of engine noise. It may be necessary to repeatedly compare the sound between the tools/methods to help locate the source of the noise.
NOTE: Make sure to use the latest scan tool software release.
If the cause is not visually evident, connect the scan tool to the DLC .NOTE: The VCM LED prove out confirms power and ground from the DLC are provided to the VCM .
If the scan tool does not communicate with the VCM :NOTE: This procedure uses multiple tools/methods to help locate the source of engine noise. It may be necessary to repeatedly compare the sound between the tools/methods to help locate the source of the noise.
Follow the steps below to help identify the source of engine noise. Compare the characteristics of the engine noise to those listed in the NVH chart.Click here to view engine noise diagnosis using a stethoscope.
Click here to view engine noise diagnosis using ChassisEAR.
Click here to view engine noise diagnosis using EngineEAR.
Click here to view engine noise diagnosis using VCMM and accelerometers.
NOTE: ChassisEAR and EngineEAR allow the use of a microphone for listening. These tools may be connected directly to the VCMM by using a 3.5mm male to RCA female adapter.
If the noise remains unclear or to verify the suspected noise from the stethoscope ChassisEAR, EngineEAR or graphed accelerometers, using a 3.5mm male to RCA female adapter, attach the ChassisEAR or EngineEAR to the VCMM . Graph all or some of the noises, as like the accelerometers.Click here to view engine noise diagnosis using VCMM and ChassisEAR.
Click here to view engine noise diagnosis using VCMM and EngineEAR.
Click here to view engine noise diagnosis using VCMM and ChassisEAR and accelerometer(s).
Click here to view engine noise diagnosis using VCMM and EngineEAR and accelerometer(s).
NVH Chart
NOTE: Possible sources and their listed actions are not limited to the symptoms provided below. Noise may be telegraphed from other areas or excited from associated parts and/or assemblies. The below chart of sources and actions are strictly suggestions and should be used as a guide.
Symptom | Possible Source |
Drone type noise |
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Drumming noise - occurs inside the vehicle during idle or high idle, hot or cold. Very low-frequency drumming is very rpm dependent |
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Engine drumming noise - accompanied by vibration |
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Rattle |
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Rattle - occurs at idle or at light acceleration from a stop |
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Moaning |
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Whine/moan type noise - pitch increases or changes with vehicle speed |
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Clunk |
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Clunk - occurs when shifting from PARK or between REVERSE and DRIVE |
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Hooting |
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Accessory drive bearing hoot - occurs at idle or high idle in cold temperatures of approximately 4°C (40°F) or colder at the first start of the day |
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Accessory drive belt noise, squeal or chirping |
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Pop noise - happens approximately 30 seconds after cold start up |
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Clunking/moaning/grinding noise |
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Humming |
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Whining |
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Whine/hum - occurs when unlocking the vehicle or opening the door with the engine off (GTDI only) |
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Whine or moaning noise |
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Whistling noise - normally accompanied with poor idle condition |
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Whine or air rush type noise |
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Chirp or whoosh sound |
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Hissing noise |
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Hissing noise - occurs during idle or high idle that is apparent with the hood open |
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Grinding noise - occurs during engine cranking |
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Engine noise, front of engine - knocking noise from lower front of engine |
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Tapping |
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Engine noise, front of engine - ticking, tapping or rattling noise from the front of the engine |
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Engine noise, upper end - ticking noise near the fuel rail and intake manifold |
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Engine noise, upper end - ticking, knocking or rattle noise that occurs during idle or high idle during the first cold start of the day and may disappear as the engine warms |
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Engine noise, upper end - occurs mostly with a warm engine at light/medium acceleration |
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Engine noise, upper end - rattling noise from the valve train. Worse when the engine is cold |
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Engine noise, upper end - pinging noise |
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Engine noise, lower end - ticking or knocking noise near the oil filter adapter |
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Engine noise, lower end - light knocking noise, also described as piston slap. Noise is most noticeable when the engine is cold with light to medium acceleration. The noise disappears as the engine warms |
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Engine noise, lower end - light double knock or sharp rap sound. Occurs mostly with a warm engine at idle or low speeds in drive. Increases in relation to engine load. Associated with a poor lubrication history |
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Engine noise, lower end - light knocking noise. The noise is most noticeable when the engine is warm. The noise tends to decrease when the vehicle is coasting or in neutral |
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Engine noise, lower end - deep knocking noise. The noise is most noticeable when the engine is warm, at lower rpm and under a light load and then at float |
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Engine noise, rear of engine - knocking noise at rear of engine |
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Slapping |
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Knocking |
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Engine vibration - vibration felt at all times |
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Engine vibration - at idle, a low-frequency vibration (5-20 Hz) or mild shake that is felt through the seat/ floorpan |
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Engine vibration - is felt with increases and decreases in engine rpm |
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Engine vibration - increases intensity as the engine rpm is increased |
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Engine vibration - mostly at coast/neutral coast. Condition improves with vehicle acceleration |
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Engine vibration or shudder - occurs with light to medium acceleration above 56 km/h (35 mph) |
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Bongo |
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Chatter |
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Chirping |
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Clicking |
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Clatter |
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Crickets |
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Dieseling |
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Quacking |
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Scratching |
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Scraping |
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Squeaking |
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Squealing |
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Thumping |
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Tin-Like |
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