Where is the knock sensor on a 2002 RX300?
The knock sensors on a 2002 RX300 are mounted on the rear of the engine block, one on each bank of the V6, and are accessible from the top once you remove the intake plenum. They connect to the engine control unit to monitor detonation and adjust timing.
Understanding their exact placement helps with diagnostics and replacement. The RX300 uses the 1MZ-FE V6 engine, which has two knock sensors located on the rear portion of the engine block, one for each bank, near the firewall. Access typically requires removal of the upper intake components and a careful path of the wiring harness to the PCM.
Knock sensor locations on the 1MZ-FE in the RX300
Before examining the locations, note that the RX300 employs two knock sensors mounted on the engine block at the rear, one on each bank. The sensors are threaded into the block just behind the cylinder heads and beneath the intake plenum, with two-wire connectors running to the ECU.
- Left/rear bank knock sensor (driver’s side): located on the rear of the engine block near the firewall, behind the intake manifold, with a two-wire harness.
- Right/rear bank knock sensor (passenger’s side): located on the opposite rear of the engine block near the firewall, also behind the intake manifold, with a two-wire harness.
Knowing these two rear-block locations helps you pinpoint and inspect or replace the sensors without unnecessary disassembly. If you’re uncertain, consult a repair manual for your exact VIN and engine revision or have a qualified technician verify the locations.
Accessing and replacing the knock sensors
To inspect or replace the sensors, you’ll typically need to gain access from the top of the engine, which usually means removing the upper intake manifold and related components to reach the sensors on the rear block faces. Below are the general steps you would follow.
- Disconnect the negative battery terminal to prevent any electrical shorts while working around the sensors.
- Remove the engine cover, intake plenum, and any hoses or components obstructing access to the rear of the engine.
- Locate the two knock sensors on the rear of the engine block, one on each bank, with their two-wire electrical connectors.
- Carefully unplug the sensors’ electrical connectors and note the orientation of each sensor’s connector for reassembly.
- Using the appropriate socket, carefully unscrew each sensor from the block, taking care not to drop debris into the port.
- Clean the mounting surfaces and install the new sensors, tightening to the manufacturer’s recommended torque (check a Lexus service manual for the exact specification).
- Reconnect the electrical harnesses, reassemble the intake and any removed components, reconnect the battery, and start the engine to verify proper operation and absence of codes.
If you are not comfortable performing this work, or if the vehicle shows knock sensor error codes after replacement, seek professional service. Accurate diagnosis may require scanning the ECU with the appropriate OBD-II tool to confirm that the fault codes have cleared and no additional timing or sensor issues remain.
Summary
For a 2002 RX300, the knock sensors are two sensors mounted on the rear of the 1MZ-FE V6 engine block—one on each bank, near the firewall. Access is usually gained from the top after removing the intake plenum. Replacement involves unplugging the connectors, unscrewing the sensors, and installing new units with proper torque, followed by reassembly and diagnostic check.
How much does it cost to replace a knock sensor on a 2002 Lexus RX300?
between $669 and $913
The average cost for a 2002 Lexus RX300 Knock Sensor Replacement is between $669 and $913. Labor costs are estimated between $464 and $680 while parts are priced between $206 and $233. This range does not include taxes and fees, and does not factor in your unique location.
What is the common fault with the Lexus RX300?
The automatic boot motor is known for failing on the RX300. If you notice that the automatic boot makes a clunking noise when you press the button to open or close it, this indicates the motor is starting to fail. If the boot does not open at all, then the motor has completely failed.
Where is the knock sensor on a 2001 Lexus RX300?
The 2001 Lexus RX300 has two knock sensors mounted on the engine block beneath the intake manifold—Sensor 1 on the front side, Sensor 2 on the rear.
Where is the knock sensor located?
A knock sensor is typically located on the engine block, often near the cylinder head and underneath the intake manifold. Its exact position depends on the engine type, but it's strategically placed to detect vibrations. For instance, in some V6 or V8 engines, there might be two sensors, one for each cylinder bank, while a four-cylinder engine usually has one in the middle of the block.
This video explains the location of knock sensors on a car engine: 53sAuto Repair GuysYouTube · Jan 30, 2022
Common locations by engine type
- Inline engines: Usually has one sensor, often located between cylinders 2 and 3, though straight-six engines can have two.
- V6 and V8 engines: Most likely to have two sensors, one on each bank of cylinders. On some models, both sensors are located underneath the intake manifold or on the passenger side forward of the starter.
- Accessing the sensor: Due to its position, access can sometimes require removing the intake manifold or getting under the vehicle.
This video demonstrates how to replace a knock sensor on a Kia Rio: 57sGoTechYouTube · May 5, 2022
