Rear Park Assist Sensors On A 2008 Es 350

[rfg08]

When I hit the switch to turn on the park assist, I get a warning on the display that all three of my rear sonar sensors are not working. Could all three be bad, or is there something common to all three that is preventing all of them from working? Thanks.

[1990LS400]

The wires for the three rear sensors could all be in the same cable if its anything like the parking aid system installed by Lexus dealers in Europe on several models: http://www.lexus-tech.eu/aimuploads/%7B9BFB5B18-7535-9E71-C492-01C5BD4B7535%7D/TPA800%20RHD%20PZ464-K0425-00%20AIM%20000%20318-2.pdf

You haven't had your rear bumper cover off the car for repairs, have you? If so, maybe someone didn't plug the sensors in.

[rfg08]

I don't think the bumper has been off, but I can't say if the previous owner had some work done on it. Its possible something back there is disconnected . I can see the two corner sensors, and they are plugged in, but I can't see or get my hand into where the center sensor is without taking the cover off. Is there any other way to test them from where the cable terminates of does the cover have to come off?

[1990LS400]

Have the rear sensors ever worked while you have owned the vehicle? And I am confused - The photos of two 2008 ES350's I'm looking at on eBay both have four rear sensors instead of three.

[rfg08]

Sorry about that, you are right, there are 4 sensors in the back, 2 are in the middle of the bumper separated by about 2 ft, and the other two are in the corners. I did notice that the center left sensor is not flush with the circular sensor holder. It has been pushed in approx. 1/16 th of an inch, and is loose on the bumper. Do you think this cold be the problem. Bob

[1990LS400]

Certainly a loose/damaged sensor would be suspicious and something to consider replacing before going further. I suppose it is possible that all four sensors have to be functional in order for any of them to provide information to the system.

Again I ask: Have the rear sensors ever worked while you have owned the vehicle? If they did, was there some "event" associated with them ceasing to work?

There should be a diagnostic procedure for your park assist system as there are for other systems in Lexus vehicles. If you are intent in diagnosing the problem yourself, you might consider getting either the repair manuals for your car or a short term ($15?) subscription to https://techinfo.toyota.com which should have the diagnostic procedures you need. Do you have the skills and tools for doing routine tests on automotive electrical systems - testing for continuity, resistance, amps, etc.?

Few people on car forums seem to buy the repair manuals for their cars or have access to https://techinfo.toyota.com . I doubt that you will fine anyone who can provide the diagnostic procedures in an electronic format. A diagnostic procedure for even a simple electronic system (e.g. seat heaters) can take up quite a few pages in the hard copy repair manuals. I don't remember threads on this or the other Lexus forums I frequent that had information about troubleshooting the park assist system.

Sometimes it's just cheaper and more efficient to take a vehicle to a knowledgeable mechanic.

[rfg08]

The answer to you question is no, the back ones have never worked since I got the car, but the front ones work fine. And yes I believe I have the ability to trouble shoot the problem, I 've been a gear head for over 50 years of tinkering with a miriad of vehicles, have a degree in electrical engineering, and spent over 20 years doing ground up restorations on three different Classic corvetttes. A1965 corvette, a 1963 fuel injected split window coupe, and AC cobra. I love cars and love the challange of fixing them. So which source do you think would give me the best bang for my buck, the toyota sight or the service manual for my car. By the way, I apprieciate the help . Oh, if there is anyone of the members willing to part with a service manual or know of a free sight to get one, let me know. Thanks.