For 2004 and newer Toyota 4Runners, checking the transmission fluid level isn’t as simple as pulling a dipstick. These models come with sealed transmissions, requiring you to monitor the transmission fluid temperature to ensure accurate level checks. Knowing your transmission temperature is crucial for maintenance and diagnosing potential issues, especially if you’re using your 4Runner for towing or off-roading. While there are a few ways to do this, using a BAFX OBD2 Bluetooth adapter with your Android device is one of the most convenient and insightful methods. Let’s dive into how you can easily monitor your 2004 Toyota 4Runner’s transmission temperature using this technology.
Traditionally, some might suggest using an infrared thermometer pointed at the transmission pan. However, this method is often unreliable and doesn’t provide the accurate readings needed for precise fluid level checks or performance monitoring. Instead, we’ll focus on two reliable methods: the paperclip trick and the more advanced, user-friendly OBD2 Bluetooth approach, highlighting the benefits of using a BAFX OBD2 Bluetooth adapter with an Android device.
Method 1: The Paperclip Trick – A Budget-Friendly Approach
If you’re looking for the absolute cheapest way to check if your transmission fluid is within the temperature range for a level check, the paperclip method is for you. This method, outlined in the Toyota Factory Service Manual (FSM), utilizes your 4Runner’s OBD port and dashboard lights. It requires no special tools beyond a simple paperclip.
The process relies on putting your 4Runner into Transmission Temperature Check Mode. It’s important to start with a cold transmission for this method to work correctly. Here’s how it works, as detailed in the FSM for a 2007 4Runner, which applies similarly to the 2004 model year and other Gen 4 4Runners:
This image from the Toyota Factory Service Manual illustrates the pin locations for the paperclip method to initiate transmission fluid temperature check mode in 2004-2009 Toyota 4Runners.
As shown in the diagram, you’ll need to insert a jumper wire or paperclip between terminals 4 and 13 of your 4Runner’s OBD port. Locate your OBD port (usually under the dashboard on the driver’s side). Despite the manual’s diagram, the OBD port in your 4Runner might be oriented upside down, but the pin positions remain the same.
A paperclip is used as a jumper wire inserted into the specified pins of the OBDII port on a Toyota 4Runner to initiate the transmission fluid temperature check mode.
With the paperclip jumper in place, start your engine. You’ll notice your dashboard lights flashing. This is normal. Now, shift your gear lever back and forth between Neutral (N) and Drive (D) every 1.5 seconds for a total of 6 seconds. If done correctly, your ‘D’ drive indicator or ‘A/T Oil Temp’ light will illuminate for about 2 seconds and then go out. This indicates that your 4Runner has entered Transmission Temperature Check Mode. In some 4Runners, like the 2007 Limited model, it’s specifically the ‘A/T Oil Temp’ light that signals this mode.
The ‘A/T Oil Temp’ light illuminates on the dashboard of a Toyota 4Runner, indicating the vehicle has entered transmission temperature check mode.
Once in this mode, remove the paperclip jumper and let the engine idle. As the transmission fluid warms up, the ‘D’ or ‘A/T Oil Temp’ light will turn on solid when the fluid reaches the minimum temperature for a level check. Have your tools and a catch pan ready because as soon as this light stays on, you need to quickly perform the fluid level check before the light starts flashing, indicating the fluid is too hot.
This paperclip method is free and utilizes readily available items, but it requires careful attention to the dashboard lights and can be a bit cumbersome. For real-time temperature monitoring and ease of use, especially for regular checks or while driving, the OBD2 Bluetooth method offers a superior experience.
Method 2: BAFX OBD2 Bluetooth & Android App – The Modern, Convenient Way
For a more user-friendly and versatile solution, consider using a BAFX OBD2 Bluetooth adapter with an Android app like Torque Pro. While this method involves a small upfront cost, the benefits of real-time temperature monitoring, ease of setup, and additional diagnostic capabilities make it a worthwhile investment for any 2004 Toyota 4Runner owner. This method allows you to conveniently monitor your transmission temperature directly from your Android device.
You’ll need two things:
- A BAFX Products Android Wireless Bluetooth OBD2 Scanner (or any ELM327 compliant OBD2 Bluetooth dongle). These are readily available online and are quite affordable.
- The Torque Pro app for Android (available on the Google Play Store for a small fee).
First, plug your BAFX OBD2 Bluetooth dongle into your 4Runner’s OBD port. Turn your ignition key to the “ON” position (without starting the engine). On your Android device, go to Bluetooth settings and pair with your OBD2 dongle. Refer to your BAFX OBD2 Bluetooth adapter’s instructions for the device name if needed.
Next, open the Torque Pro app and set up your vehicle profile if you haven’t already. Then, navigate to “Settings” > “Manage extra PIDs/Sensors” > “Add custom PID” > “OK”.
Screenshot from the Torque Pro Android app demonstrating the initial steps to add a custom PID for transmission temperature monitoring on a 2004-2009 Toyota 4Runner.
Now, you’ll need to enter the custom PID information for 4th Gen Toyota 4Runners (2004-2009):
- OBD2 Mode and PID:
21d9 - Long Name:
Transmission Temperature(or whatever you prefer) - Short Name:
Trans Temp(or something similar) - Minimum Value:
0 - Maximum Value:
300 - Scale factor:
x1 - Unit type:
F - Equation:
(((((G*256)+H)*(7/100))-400)/10)
Screenshot from the Torque Pro app showing the input fields for the custom PID, specifically highlighting the equation required to read transmission temperature on a 4th Gen Toyota 4Runner.
Ensure you enter the equation exactly as shown, paying close attention to parentheses and no spaces. A green checkmark should appear once the formula is correctly entered. Click “OK”.
With the custom PID created, you need to add a gauge to your Torque Pro dashboard to display the temperature. From the main screen, select “Realtime Information” > “Menu” > “Add display”. Choose a display type (e.g., “Digital display”), select the sensor name you created (e.g., “Trans Temp”), and choose a widget size. You can now position your new transmission temperature gauge on your Torque Pro dashboard.
Screenshot from the Torque Pro app illustrating the steps to add a display gauge to monitor real-time data, in this case, transmission temperature.
Screenshot of the Torque Pro app dashboard with a newly created digital display gauge showing real-time transmission temperature readings for a Toyota 4Runner.
This custom PID and formula are verified to work on 2004-2009 Gen 4 Toyota 4Runners. For newer Gen 5 4Runners (2010+), the PID and equation are different (details are usually available online in 4Runner forums).
While Torque Pro is a popular choice, other OBD2 apps like OBD Fusion also work with BAFX OBD2 Bluetooth adapters and can monitor Toyota transmission temperatures. OBD Fusion may require purchasing the app and an enhanced diagnostics add-on for Toyota-specific features, but some users find it easier to set up than manually entering custom PIDs.
Conclusion
Monitoring your 2004 Toyota 4Runner’s transmission temperature is essential for proper maintenance and ensuring the longevity of your vehicle. While the paperclip method provides a free, basic solution for fluid level checks, the BAFX OBD2 Bluetooth adapter combined with an Android app like Torque Pro offers a more convenient, accurate, and feature-rich approach. With real-time temperature monitoring at your fingertips, you can confidently maintain your 4Runner’s transmission and even observe temperature fluctuations during driving conditions, providing valuable insights into your vehicle’s performance. Whether you choose the budget-friendly paperclip or the technologically advanced BAFX OBD2 Bluetooth method, staying informed about your transmission temperature is a crucial step in 4Runner ownership.
