2003 Lexus RX300 Problems

RepairPal has identified the most common problems with the 2003 Lexus RX300 as reported by actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.

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8
Known Problems

The 1998-2003 Lexus RX300 may start and stall, or start and run at very low engine speeds when the engine is cold. 

The issue is a failed or dirty idle air control valve. This valve is mounted under the throttle body, and modulates airflow to the engine under certain conditions. When the valve becomes dirty, or when the valve fails, proper airflow to the engine is not achieved. This results in start and stall, and low RPM.  

To correct the issues, the idle air control valve will need to be tested, and cleaned or replaced. 

To help decrease the frequency of this issue, change the air filter no less than once per year. 

The Lexus RX300 has a known issue with the valves that if left unchecked, will cause burned valves and engine performance issues. 

The engine ‘breathes’ through valves that are pushed open by the camshaft, and closed by springs. When valves are closed, they seal against a valve seat. In this vehicle, the valve seat is too soft, so after the valve contacts it thousands of times, it becomes crushed. Once it is crushed, the valve can no longer make a proper seal, and the valves erode due to extreme temperature (burnt valve).

Symptoms related to this issue:

To repair the burnt valves, the cylinder head must be removed and rebuilt, which is a costly internal engine repair, however, this issue can be prevented through inspection and adjustment of valve clearances every 40,000 miles.

Drivers of the Lexus RX300 may notice excessive oil consumption between oil changes, even to the extent of the engine oil warning light displayed on the multi-function display.

This issue is known to be caused by infrequent oil changes causing engine sludge, or worn piston rings. 

The engine should be cleaned of oil sludge, and if oil consumption remains excessive, the engine may need new piston rings, or other internal components replaced. 

To avoid this issue, change the engine oil and filter every 3,000 miles, and ensure the proper grade of oil is used. 

Debris can get into the idle air control valve. This will restrict the air flow into the engine, causing idle speed and/or stalling when cold. The valve can be cleaned or replaced to correct this concern.

The Check Engine Light may illuminate because the mass air flow sensor sends incorrect information to the engine control computer. This can cause a loss of power on acceleration. A failed mass air flow sensor will require replacement.

On higher mileage vehicles, an engine misfire may develop and/or the Check Engine Light may illuminate due to a failed ignition coil. It is not uncommon to replace all the coils when the first one fails in order to prevent return trips to the repair shop.

The Check Engine Light may come on because a component of the oxygen sensor stops working. Replacement of the failed sensor should correct this concern.

Intermittent failure of the purge control valve in the evaporative emissions (EVAP) system may cause the Check Engine Light light to illuminate.