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Hybrid TechnologyUnique topics related to the 2010 - 2015 RX450H model hybrid drivetrain and other features/options found only on the RX450H. Please use the main forum for discussion about shared components with other third generation RX models.
I have a 2010 RX450h and a few weeks ago, i noticed the rear ultrasonic sensors are beeping while driving on the road. Thought the distance sensor system needs replacing. Then 2 weeks ago, i decided to check the reverse lights and sure enough, they were lit irrespective of whether the car is in P, D or N. The scanner registers the changes in the transmission selections but the reverse lights and reverse distance sensor remained on (because they are on the same circuit). So, how can I check and possibly change a faulty relay for the reverse light on a hybrid car (as i understand the older non-hybrid cars normally have a simple on/off switch installed into the transmission box to monitor when the gear shifts to reverse.
Yes, a short sounds very likely. But where do I start? Is there somewhere I can get a circuit diagram to look for possible point of shorts. Basically where the cable from the reverse lights ends so I can simply follow the voltage gain.
Does the R indicator work properly? Some other Lexus models of this era have a "luggage room ECU" which in part controls the reverse lights. Can get a wiring diagram here, couldn't find one online for free. https://techinfo.toyota.com
Yes, the "R" comes up on Dashboard. Also the scanner correctly indicates the shift from P to R to N to D etc. All normal from computer and shift stick side.
Update: Found the diagram!!! Looks simple but any suggestions?
Last edited by gordon3d; Aug 23, 2021 at 06:14 AM.
Reason: Update
If you have a test lamp or voltmeter .. check the presence of +12v on terminal 3 of the backup relay [it should read 12v]
Now check terminal 5 [My guess is will show 12v] ..... it is expected to be 0v in Parrk
Now check terminal 1 [it is expected to be 0v in Park]
If your observations match then the relay contacts are fused tighter and are not separating on absence of 12v on terminal 1.
If you see 12v on 1 then trace back to 15 of Power management control unit. If you see 12v then confirm the display that it showing "Park". At that time you have to check the PRND switch of the control unit has gone bad.
Salim
Last edited by salimshah; Aug 24, 2021 at 10:02 PM.
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Reverse lights always on
