If you’re a proud owner of a 1999 Lexus RX 300 AWD and need to run a diagnostic check, locating the OBD2 port is your first step. This article will guide you to the 1999 Lexus Rx 300 Awd Obd2 Location and also discuss a peculiar issue that some owners of older Lexus and Toyota vehicles have encountered when using OBD2 scanners: the unexpected triggering of VSC and TRAC OFF lights.
Locating the OBD2 Port in Your 1999 Lexus RX 300 AWD
The OBD2 port, or On-Board Diagnostics II port, is a standardized connector in modern vehicles that allows access to the car’s computer for diagnostics and monitoring. For the 1999 Lexus RX 300 AWD, you’ll typically find the OBD2 port located inside the cabin.
Generally, you should look for the OBD2 port in the driver’s side footwell area. It is usually situated beneath the dashboard, within easy reach. You might need to get down and look under the dash panel, often near the steering column or to the left of it. The port is usually dark in color and has a trapezoidal shape with 16 pins.
Once you’ve located the port, you can connect your OBD2 scanner to read diagnostic trouble codes (DTCs) or monitor live data from your vehicle’s systems.
The Curious Case of VSC and TRAC OFF Lights After OBD2 Scan
Now, let’s delve into a rather unusual but not uncommon issue reported by owners of older Toyota and Lexus vehicles, including the 1999 Lexus RX 300 AWD. Some users have experienced the Vehicle Stability Control (VSC) and Traction Control (TRAC OFF) lights illuminating on their dashboard immediately after plugging in an OBD2 scanner, even when no prior issues were indicated.
This problem has perplexed many and often leads to unnecessary concern and potentially costly trips to dealerships. It’s crucial to understand that in these cases, the act of connecting the OBD2 scanner itself can trigger this issue, not necessarily because there was an underlying problem detected by the scan.
Why Does This Happen? Protocol Mismatch and Yaw Sensor Calibration
The likely culprit behind this phenomenon is related to the different communication protocols used in OBD2 systems over the years and how early Toyota and Lexus ECUs (Engine Control Units) interact with modern scanners.
OBD2 scanners are designed to communicate with vehicles using a range of protocols, attempting to connect using the oldest ones first. However, in some older Lexus and Toyota models, it appears that scanners might inadvertently connect using a newer protocol. When this happens, the scanner can unintentionally send signals through specific pins in the Data Link Connector (DLC) – the OBD2 port – that are interpreted incorrectly by the vehicle’s computer.
Specifically, this unintended communication can sometimes lead to the erasure of the Yaw Sensor Zero Point Calibration data stored in the vehicle’s computer. The yaw sensor is crucial for the VSC and TRAC systems to function correctly, as it detects the vehicle’s rotation rate. Without proper calibration, the system cannot accurately determine if the vehicle is skidding, leading to the VSC and TRAC systems being deactivated as a safety measure, and consequently, the warning lights illuminating.
Resetting the vehicle’s computer might temporarily turn off the VSC and TRAC OFF lights upon engine start. However, as soon as the vehicle moves a short distance, typically around 10 feet, these lights will reappear, indicating that the calibration issue persists.
Resolving the VSC and TRAC OFF Lights Issue: Zero Point Calibration
Fortunately, this issue is usually not indicative of a mechanical failure and can often be resolved by recalibrating the Yaw Sensor Zero Point. There are primarily two methods to achieve this: manual reset and scanner-based reset.
1. Manual Zero Point Calibration Using a Jumper Wire
A manual reset can be performed by using a simple jumper wire to short specific terminals in the OBD2 port at precise intervals while turning the ignition switch on and off. This procedure essentially forces the system to re-learn and store the correct zero point calibration for the yaw sensor.
The process generally involves:
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Ensuring the vehicle is parked on a level surface and the gear lever is in the “P” (Park) position.
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Turning the ignition switch to the “ON” position.
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Using a jumper wire to repeatedly short and open the connection between the “Ts” and “CG” terminals of the DLC3 (OBD2 port) four times or more within 8 seconds. Crucially, the exact pinout for “Ts” needs to be correctly identified for your specific vehicle year and model.
Example DLC3 Diagram (Note: Pinout may vary) -
Verifying that the VSC indicator light illuminates, indicating the zero point has been erased.
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Turning the ignition switch to the “OFF” position and disconnecting the jumper wire.
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Turning the ignition switch back to “ON” and observing the VSC warning light behavior to confirm successful recalibration.
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Driving the vehicle to ensure the VSC and TRAC OFF lights remain off.
Important Caution: The manual reset procedure requires accurate identification of the “Ts” pin in your 1999 Lexus RX 300 AWD’s OBD2 port. There are reports of varying pinout diagrams, with “Ts” potentially being pin 12, 13, or 14. Incorrectly shorting pins could potentially damage your vehicle’s ECU. Therefore, proceed with extreme caution and only if you are confident in identifying the correct pins, ideally with a verified repair manual for your specific vehicle.
2. Scanner-Based Zero Point Calibration
The second method involves using an OBD2 scanner that has the function to reset the Yaw Sensor Zero Point Calibration. Interestingly, some older scanners are reported to be more effective at this specific reset than newer, more advanced models.
If you have access to an older scanner, or know someone who does, it might be worth trying this method first. The process usually involves navigating the scanner’s menu to find the “Yaw Sensor Calibration” or “Zero Point Calibration” function under the ABS or VSC system settings. Follow the scanner’s on-screen instructions to perform the reset.
3. Seeking Professional Help
If you are uncomfortable performing the manual reset or do not have access to a suitable scanner, the safest option is to take your 1999 Lexus RX 300 AWD to a trusted mechanic or Lexus dealership. Knowledgeable technicians should be familiar with this issue and be able to perform the Zero Point Calibration using professional diagnostic tools. In many cases, this reset can be done within an hour of labor, which is significantly less expensive than replacing components like the yaw sensor, which some less informed dealerships might suggest.
Prevention and Advice
To minimize the risk of encountering this VSC/TRAC OFF light issue after using an OBD2 scanner on your 1999 Lexus RX 300 AWD, consider these points:
- Exercise Caution with OBD2 Scanners: Be aware that this issue can occur on older Lexus and Toyota models.
- Verify Pinouts if Attempting Manual Reset: If considering a manual reset, prioritize obtaining a reliable and verified pinout diagram for your specific 1999 Lexus RX 300 AWD before attempting to short any pins.
- Consider Older Scanners for Reset: If you have access to or can borrow an older OBD2 scanner, it might be more likely to have the necessary function to reset the Yaw Sensor Zero Point Calibration effectively.
- Don’t Panic: If the VSC and TRAC OFF lights illuminate after an OBD2 scan, remember it might be due to this calibration issue and not a major mechanical problem.
By understanding the location of your 1999 lexus rx 300 awd obd2 location and being aware of this potential OBD2 scanner-related issue, you can approach diagnostics and troubleshooting with greater confidence and potentially save yourself time and unnecessary expenses.
References:
- https://pinoutguide.com/CarElectroni…c_pinout.shtml
- https://www.clublexus.com/forums/mai…ml#post5858288
- https://www.clublexus.com/forums/mai…0-post5858288 (Duplicate link in original, kept for completeness)
