2004 Hyundai Sonata Repair and Maintenance
A guide to problems, costs, maintenance and repair for your 2004 Hyundai Sonata
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2004 Hyundai Sonata ProblemsRough Idle Due to Faulty EGR Switching Valve
On the 2.7L V6 and 2.4L 4 Cylinder, a defective exhaust gas recirculation (EGR) switching valve may cause an intermittent rough or unstable idle engine.
If you experience excessive engine noise on startup (after the engine has been turned off for several hours) that lasts for more than five or six seconds, turn off the engine and check that the engine oil level is correct. If the oil level is correct, the noise may be caused by the timing chain tensioner. Hyundai has an improved tensioner to correct this problem.
Problems with the accelerator pedal position switch may cause the Check Engine Light to illuminate; an improved switch is available to fix this problem.
2004 Hyundai Sonata Questionsbrake light won't turn off (1 answer)
This was my reading when it went through Emissions.
Monitors Not Ready:
MIL Remains lit at key-on-engine-running
MIL Commanded On
1 Trouble Code Reported:
P0056 HO2S Heater Circuit Bank 2 Sensor 2
When I start the car from a cold start the ABS & Hand Brake Light goes off. After a warm start the ABS & Hand brake light stays on.