Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Stop Light Relay Circuit (C1A4B)
DESCRIPTION
When a stop light relay circuit malfunction signal sent from the vehicle stability control system is detected by the clearance warning ECU assembly, DTC C1A4B is stored.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area |
|---|---|---|---|
| C1A4B | Stop Light Relay Circuit | Stop light relay circuit malfunction | Vehicle stability control system |
CAUTION / NOTICE / HINT
NOTICE:
-
After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.
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After replacing an ultrasonic sensor or the clearance warning ECU assembly, perform the necessary procedures (adjustment, calibration, initialization or registration).
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-
When DTC C1A4B is stored, there may be a malfunction in the lighting system. Inspect the lighting system before performing the following procedure.
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PROCEDURE
| 1. | CHECK DTC OUTPUT |
(a) Using the Techstream, check for DTCs according to the prompts on the screen.
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HINT:
After turning the engine switch from off to on (IG), wait 4 seconds or more before checking for DTCs.
Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Trouble Codes(b) Clear the DTCs according to the screen on the Techstream.
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(c) Recheck for DTCs.
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HINT:
- DTC C1A4B is stored when a malfunction signal sent from the vehicle stability control system is detected.
- If the malfunctioning part has been repaired or replaced before rechecking for DTCs, DTC C1A4B will not be output again.
-
If DTC C1A4B is output frequently, duplicate the conditions that cause the problem symptoms and perform the inspection again, even though the DTC was not output when rechecking for DTCs.
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| Result | Proceed to |
|---|---|
| DTC C1A4B is output | A |
| DTC C1A4B is not output | B |
| A | .gif) | GO TO PRE-COLLISION SYSTEM |
| B | | USE SIMULATION METHOD TO CHECK |
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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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