At 19,000 miles the rear vehicle sensors are starting to act screwy. It does not happen all the time so I know I will have trouble reproducing it for the dealer next week at oil change time. Here is what is happening. Anyone have any ideas what to check?

When shifted from park to reverse, sometimes there is a constant beep as if there is something less than 10 inches away. (There is not.) Other times it beeps and then turns off and then on etc. etc. with no rhyme or reason related to anything behind the truck. Sometimes when backing up it will suddenly sound a solid beep. After slamming on the brakes, it is apparent there is nothing there.

Yes the sensors are clean, no dirt or mud covering them.

I know some will say that these sensors are no substitute for the old fashioned way of backing up and I agree, but they sure do help sometimes when they are working properly.

Thanks for any suggestions as to what may be happening.

 

Are you backing down a hill, sloped driveway, etc.? When I back down out of my sloped driveway it beeps, probably picking up the roadway from that steep angle. Other than that they work great and I do just use it as an aid, not a substitute. Hope you find out the problem.

Mike

 

No. I am aware of the things you describe, but those things are understandable and make sense as to how the system works.

Mine alarm for no reason. I actually let the truck sit in reverse in a flat, open, parking lot for several minutes yesterday. (Not moving) The sensors would eventually go off for no reason, stop and then start again a few minutes later. So, I actually may be able to show the dealer something to get them working on it.

 

Other vehicles with similar RADAR sensors nearby?
Bank or other alarm system nearby?
Auto door openers nearby?

Could be simple receiver overload from near same frequency systems.

 

By chance did you have your tail gate down? Mine go off sometimes after I've washed my truck and the sensors are still wet.
Bert

 

Thanks for the ideas, but no radar, alarms, or door openers nearby. Yes it will go off if tail gate is down, but that's not the case here.

Unfortunately, when I tried to reproduce it yesterday for a friend, it would not happen. We all know what the dealer will say if that happens when I bring it in.

The biggest problem with this is when I am backing up free and clear and it goes off. It sounds a solid tone like there is something 10 inches or less away, so I slam on the brakes, have a heart attack, and nothing is there.

When it does it, it is always a solid alarm. If you stay put in reverse, it will go off after 5 to 30 seconds, then go on again and so on.

 

Well, took it in to the dealer for oil change and another attempt at fixing the a/c. (that's another post)

Anyway, of course the back up sensors would not malfunction while the dealer had it. They checked a bunch of things, but all checked out so they could not fix it. Shortly after leaving the dealer, it did it and has several times since. Very frustrating!

 

Mine work fine - worth the 245 dollar option - of course I only have 4k on this new one so we'll see what happens - good luck!

 

Yes, mine worked fine too, for the first 18,000 miles!

 

I can't guarantee you this is your culprit, but from experience I would say that what your experiencing sounds a lot like range gate sycronization. I am an Electronic Signals Intelligence Exploitation Analyst for USAF. We monitor and analyse foreign and domestic radars for a living. Please bare with this explination, I've tried to simplify it to be as un-technical as possible.

It very easy for a radar aperature to come off sync with the pulse emission. To keep a radar from being overloaded by it's own returns, there is a "gate" that raises and lowers in front of the return "eye" of the radar. This accepts only radar returns in the system's intended range distance. Those returns that are received while the "gate" is up will be ignored. In most newer radars, including small pulse doppler sensors (AKA reversing aids) the "gate" is software so the computer filters out unwanted returns.

It sounds like your "gate" may be faltering and not raising or lowering at the right intervals (Micro-Nano Second timing) and getting continuous stray return signals. Most likely a faulty control chip. This would be a come and go error until the chip's problem progressed further. Most service centers wouldn't know how to check/diagnose/repair this issue.

Jeff

 

Jeeeesh! I love it when you talk that way! ha ha ha

 

Is the control chip that you refer to expensive and hard to change or easy to replace?

The real problem here is that unless the dealership can duplicate and document the problem, they say Ford will not authorize a warrenty repair. It has been doing it for about 2 months and 2,000 miles. It has not progressed to being any worse since it started. I would estimate it happens 10 to 20 percent of the time you are backing up. Sometimes it won't happen for several days, then it will happen several times in one day.

 

I wouldn't suggest attempting to replace the "chip" unless your use to working on printed circuit boards. Most likely you'll need to replace the entire control module. Be careful messing to much with the sensors themselves, It may be a low power Radio Frequency but still enough to give you one hell of a headache! This may be a case where the part is as expensive as the whole system. I would wait till the problem is proveable or just doing it a lot and make Ford pay. But that's just me. It has got to be annoying.

Jeff