Lexus V8 Engines LLCOBD2 / DLC3 Client Plug Guide
No Accelerator Pedal Connection – Cable-Throttle Applications
1st Gen 2UZ and 1UZ VVT cable-throttle diagnostic connector wiring
Build-Specific Confirmation
Always confirm connector orientation, terminal location, wire color, circuit function, signal direction, polarity, fuse protection, and build-specific instructions before final installation. Do not wire by color alone.
Connector Visuals
Overview
The 6-pin OBD2 client plug provides the diagnostic and programming-related circuits from the engine harness to the customer-supplied or supplied 16-pin OBD2/DLC3 connector.
Correct OBD2 wiring is required for scan tool communication, diagnostic checks, data viewing, and ECU programming where supported by the ECU and calibration.
Important
This guide covers the vehicle-side OBD2/DLC3 diagnostic client plug for applications where the accelerator cable attaches directly to the throttle body. It does not include an electronic accelerator pedal connector and must not be used to wire a drive-by-wire pedal unless the supplied harness specifically requires it.
General Information Notice
This document is provided for general information and customer reference only. Final wiring must be verified against the exact harness supplied and the vehicle-side circuit being connected.
Quick Start: Critical Connections
| Function Group | Circuit / Pin | Wire(s) | Customer Connection |
|---|---|---|---|
| TC | Client Pin 1 | White / Pink | Connect to OBD2 Pin 13. |
| SIL | Client Pin 2 | White / Green | Connect to OBD2 Pin 7. |
| B+ | Client Pin 3 | Red | Connect to OBD2 Pin 16 with permanent fused +12V. |
| RPM | Client Pin 4 | White / Blue | Connect to OBD2 Pin 9. |
| WFSE | Client Pin 5 | White | Connect to OBD2 Pin 15 where programming support is required. |
| Ground | Client Pin 6 | Brown | Connect to OBD2 Pins 4 and 5. |
Wire Color / Tracer Reference
Stripe/tracer colors are shown as diagonal bands on the wire. The first color is the base wire color. The second color is the stripe/tracer color.
Full Pinout Reference
| Pin | Wire Visual | Circuit / Function | Signal Type | Notes |
|---|---|---|---|---|
| Pin 1 | White / Pink | TC | Diagnostic/test terminal | Connect to OBD2 Pin 13. Keep isolated during normal operation. |
| Pin 2 | White / Green | SIL | Serial communication line | Connect to OBD2 Pin 7. Do not connect to power or ground. |
| Pin 3 | Red | B+ | Permanent +12V supply | Connect to OBD2 Pin 16. Use proper fuse protection. |
| Pin 4 | White / Blue | RPM | Engine speed signal | Connect to OBD2 Pin 9. Do not use as a power source. |
| Pin 5 | White | WFSE | Programming/write-enable circuit | Connect to OBD2 Pin 15 where supported. Do not power or ground unless the procedure calls for it. |
| Pin 6 | Brown | Ground | Ground supply | Connect to OBD2 Pins 4 and 5 with low-resistance ground continuity. |
Detailed Circuit Notes
OBD2 power and ground
- Verify battery voltage at OBD2 Pin 16 to Pins 4 or 5 before plugging in a scan tool.
- Ground pins 4 and 5 should be tied cleanly to the harness ground wire.
- Poor ground quality can cause communication faults and unreliable programming.
Communication circuits
- SIL must remain isolated from B+ and ground.
- TC should not be permanently grounded or powered unless a specific test procedure requires it.
- WFSE must be used only for supported programming/write-enable functions.
First Test Checklist
| Item | Check |
|---|---|
| Pin 16 power | Permanent fused +12V present at OBD2 Pin 16. |
| Ground | OBD2 Pins 4 and 5 have low resistance to battery negative. |
| SIL isolation | OBD2 Pin 7 is not shorted to power or ground. |
| Scan tool | Scan tool powers up and communicates before road testing. |
Troubleshooting Quick Reference
| Symptom | Items to Check |
|---|---|
| Scan tool will not power up | Check fused B+ at Pin 16 and grounds at Pins 4 and 5. |
| No communication | Check SIL on Pin 7, TC isolation, ECU power, and ground. |
| Programming fails | Check WFSE Pin 15 wiring and confirm the ECU/calibration supports programming. |