Canada - Wiper System - Rain Sensor Diagnostic/Operation System
BulletinTSB2112
Issue Date
April 14, 2005
Title
RAIN SENSOR DIAGNOSTICS AND SYSTEM OPERATION
Component
BODY ELECTRICAL
Models
'04 - '05 RX330
INTRODUCTION:
The information provided in this bulletin is provided to improve diagnostic accuracy and improve general understanding of the rain sensor (AUTO Wiper) system operation. Should a customer describe problems with intermittent or improper rain sensor operation, please follow the Diagnostic Information section of this bulletin.
APPLICABLE VEHICLES:
- 2004 - 2005 model year RX330 vehicles.
REQUIRE TOOLS & MATERIAL:
WARRANTY INFORMATION:
DIAGNOSTIC INFORMATION:
1. Please verify whether the vehicle has a Lexus original equipment windshield or an aftermarket installation.
NOTE:
If the vehicle windshield is not Lexus original equipment, the rain sensor may NOT operate properly due to variations in the glass, tinting, etc.
2. View the Rain Sensor Tape through the windshield and verify if there are bubbles or contaminants visible.
If there are bubbles or contaminants visible in the Rain Sensor Tape, please remove and replace the Rain Sensor Tape (P/N: 89944-50011) as described in the the Rain Sensor Tape Replacement section in this bulletin.
3. Test the rain sensor operation by spraying/misting water in the rain sensor area of the windshield with the wipers in the AUTO mode.
NOTE:
The rain sensor may NOT operate properly if a large stream of water (i.e., garden hose) is applied directly to the rain sensor area of the windshield.
4. If the system does not operate, diagnose problems by referring to ETAS: 2004-2005 model year RX 330 Repair Manual: Diagnostics: Wiper and Washer System: Problem Symptoms Table.
If the system operates as described in this bulletin, it is operating as designed.
RAIN SENSOR TAPE REPLACEMENT:
1. Remove the rain sensor.
A. Unlock the stopper by pulling it down and remove the rain sensor.
B. Disconnect the connector.
2. Remove the used Rain Sensor Tape from the windshield or rain sensor.
NOTE:
Be sure NOT to touch the lens surface of the rain sensor.
3. Clean the surface of the glass with an alcohol-based cleaner.
NOTE:
Do NOT use a shop rag to clean the window prior to installation as oil/grease substances on the windshield will inhibit a good bond between the Rain Sensor Tape and the windshield.
4. Apply the new Rain Sensor Tape on the lens surface of the rain sensor as indicated.
NOTE:
- Be sure NOT to touch the lens surface of the rain sensor or the Rain Sensor Tape itself.
- Ensure that no bubbles or contaminants are present in the tape.
If there are bubbles or contaminants present in the tape, apply new tape.
5. Install the rain sensor.
NOTE:
After installing, check again to make sure no bubbles or contaminants are present in the tape.
WIPER SYSTEM DESCRIPTION:
- A wiper system with a raindrop sensing function has been adopted as optional equipment.
- As a rule, the control of the wiper operation is affected by the wiper ECU. However, the control of the raindrop sensing function is affected by the rain sensor.
- This system has functions:
VEHICLE SPEED - SENSING, ADJUSTABLE INTERVAL (INT) FUNCTION:
This function controls the interval time of the wipers in accordance with the vehicle speed when the wiper switch is in the AUTO position. The interval time adjusting range consists of 3 steps, which can be selected by operating the interval adjuster. The interval time can be controlled steplessly within each range.
VEHICLE SPEED SWITCHING FUNCTION:
This function automatically switched to the intermittent operation when the wiper switch is in the LO position and the vehicle is stopped. To perform this function, the stopping and driving conditions of the vehicle are determined as described below.
- Driving Judgement: When the vehicle speed is other than 0 mph/kmh or the stop light and the parking brake are OFF and the shift lever is in a position other than P or N.
- Stopping Judgement:When a condition other than the driving judgement has been detected.
When the vehicle is stopped, moving the wiper switch from the AUTO or HI position to the LO position causes the wipers to operate 3 times at the low speed and then automatically switch to intermittent operation with an interval time of approximately 2.5 seconds. When the vehicle is being driven and the switch is in the LO position, stopping the vehicle causes the wipers to operate twice and then switch to intermittent operation with an interval time of approximately 2.5 seconds.
With this function, when the wiper switch is in the OFF or AUTO position, turning the washer switch ON for approximately 0.2 seconds or longer causes the washers to operate, and after the washer switch has been turned OFF, the wipers operate in unison 3 times at the low speed. Approximately 3 seconds (when the vehicle speed is between 0 to 36 mph [0 to 59 km/h]) after the low-speed operation of the wipers has been completed, the wipers operate once again to wipe off the washer fluid that has dripped. The drip prevention interval times are shown in the table according to the vehicle speed.
RAIN SENSING FUNCTION:
When the wiper switch is in the AUTO position, this function uses a rain sensor that is mounted on the front windshield glass to detect the amount of raindrops and controls an optimal wiping timing accordingly. The rain sensor consists mainly of 4 LEDs (Light Emitting Diode) that emit infrared rays and 2 photo diodes that receive those rays. The detection method is based on the infrared rays that are reflected by the front windshield glass.
For example, if no raindrops are present in the detection area, the infrared rays emitted by the LED are all reflected from the windshield glass and are received by the photo diode. If raindrops are present in the detection area, a portion of the emitted infrared rays penetrates with the change of index of reflection outward of the windshield glass via the raindrops, thus reducing the amount of infrared rays that are received by the photo diode.
The amount of this reduction is then used to detect the amount of raindrops. Thus, this function controls the INT, LO, and HI operations in order to operate the wipers at an optimal wiping timing.
NOTE:
If the Rain Sensor Tape has been peeled during a windshield glass replacement, make sure to affix new Rain Sensor Tape. Failure to do so will lead to a system malfunction.