Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Vehicle Speed Signal Circuit between Navigation ECU and Combination Meter
DESCRIPTION
The navigation ECU receives a vehicle speed signal from the combination meter assembly.
HINT:
- A voltage of 12 V or 5 V is output from each ECU and then input to the combination meter assembly. The signal is changed to a pulse signal at the transistor in the combination meter assembly. Each ECU controls its respective systems based on this pulse signal.
- If a short occurs in any of the ECUs or in the wire harness connected to an ECU, all systems in the following diagram will not operate normally.
WIRING DIAGRAM
PROCEDURE
| 1. | CHECK COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM) |
| (a) Check the output waveform. (1) Remove the combination meter assembly with the connector still connected. (2) Connect an oscilloscope to terminal J10-19 (+S) and body ground. (3) Turn the engine switch on (IG). (4) Turn a wheel slowly. (5) Check the signal waveform according to the condition(s) in the table below.
OK: The waveform is similar to that shown in the illustration. HINT: When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows. |
|
| NG |  | GO TO METER / GAUGE SYSTEM |
|
| 2. | CHECK NAVIGATION ECU (INPUT WAVEFORM) |
| (a) Check the input waveform. (1) Remove the navigation ECU with the connector(s) still connected. (2) Connect an oscilloscope to terminal J153-9 (SPD) and body ground. (3) Turn the engine switch on (IG). (4) Turn a wheel slowly. (5) Check the signal waveform according to the condition(s) in the table below.
OK: The waveform is similar to that shown in the illustration. HINT: When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows. |
|
| OK | | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
AVC-LAN Circuit
DESCRIPTION Each unit of the audio and visual system connected to the AVC-LAN (communication bus) transmits switch signals via AVC-LAN communication. If a short to +B or short to ground occurs in the ...
Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter
DESCRIPTION The stereo component amplifier assembly receives a vehicle speed signal from the combination meter assembly to control the ASL function. HINT:
A voltage of 12 V or 5 V is output from ea ...
Other materials:
Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Audio And Visual System (for 12.3 Inch Display): Switch Lights of Remote Touch Always Illuminate or cannot be Controlled Using Rheostat
DESCRIPTION Power is supplied to the remote touch (remote operation controller assembly) switch illumination when the light control switch is in the tail or head position. HINT:
When the remote touch (remote operation controller assembly) is in self-diagnostic mode, its switch illumination may re ...
Lexus RX (RX 350L, RX450h) 2016-2025 Owners Manual > Using the driving support
systems: Driving assist systems
To keep driving safety and performance, the following systems operate
automatically
in response to various driving situations. Be aware, however, that
these systems are supplementary and should not be relied upon too heavily
when operating the vehicle.
ECB (Electronically Controlled Brake Syst ...
Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual
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