On-board diagnostics

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The UZZ32 Soarer features on-board diagnostics which can assist in troubleshooting. Various ECUs watch for eg sensor errors and store relevant error codes for retrieval. The user can then lookup the error code to help understand and address the cause.

The process for using the on-board diagnostic is, in summary:

  • Clear pre-existing error codes
  • Enable test mode
  • Test drive the vehicle
  • View the error codes

Clearing error codes

Since error codes are not automatically cleared (nor time-stamped), it is recommended that you clear any existing error codes before proceeding with the diagnostics. Otherwise, you are likely to be confused by old error codes that are likely to be irrelevant either because the issues have since been resolved or were false-alarms to start with.

The options for clearing the error codes are:

  • Remove the EFI fuse (the 30A fuse located in the under-the-bonnet fuse block)
  • Disconnecting the battery

Power needs to be removed for 10 seconds to ensure that the error codes are cleared.

Entering Diagnostic Mode

To enter diagnostic mode:

  • Locate the DLC1 connector under the bonnet and flip up the cover
  • Remove the bridging pin between WA and WB
  • Bridge the TC and E1 ports using eg a piece of wire
  • Turn the ignition on and check the dash to ensure that test mode is active

Test Drive

The purpose of the test drive is not just to replicate the error conditions, but also to ensure that the appropriate sensors are activated. Consequently, the test drive should include:

  • Open the door
  • Press 'all' the switches (Suspension Height, ECT Mode, TRC, Overdrive, Autodrive/Cruise Control, Suspension on/off)
  • Drive > 25 km/hr
  • Stop the vehicle

If the test drive does not include the above, you should receive error codes indicating, eg, that the wheels have not turned.

Viewing Diagnostic Codes

  • While in diagnostic mode, press the Scroll button on the dash
  • This cycles through the available systems (eg ___, ___, ____ and ____) and displays either <System> OK or <system> NG (No Good), eg TRC OK, ABS NG etc.
  • If a component is shown as NG, stay on that screen and the dash will start scrolling through the various error codes, eg ABS 21 ABS 22 etc.
  • The error codes will be displayed in increasing order and end with a [] on the dash

Looking up the error codes

The meaning of the respective error codes can be looked up in the manuals as well as on many websites. Some codes are common to various Toyota / Lexus vehicles, while others have a specific meaning on the UXX32.

Connectors

There are two diagnostic ports on the UZZ32:

  • DLC1 is the rectangular port on top of the engine
  • DLC2 is the circular port in the vehicle cabin

Each port has multiple pins, some (but not all) of which exist on both connectors. It is also possiblt that the pins available will vary depending on the year of manufacture.

Protocols

The UZZ32 Soarer uses a pre-cursor to OBDII. Hence, OBDII scan tools will not work.


References

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