cam/crank shaft position sensors failure

[sifan]

My 2003 Toyota Echo with 127K miles finally left me stranded the very first time since new at a parking lot. Three hours earlier its engine died without warning on a busy interstate highway. I pulled it over to the shoulder immediately and was able to restart the engine with CEL came on. After the replacement of both camshaft and crankshaft position sensors the engine runs like new.

I have diligently upkept my car, but the early warning signs of both failing sensors are also shared by bad spark plugs, clogged fuel injectors, etc. It is very hard to know exactly when to replace these sensors before they fail totally. Just few weeks ago I replaced the plugs, air filter, PCV valve, and ran several Techron treatments consecutively. I could see the improvement in engine performance, but then this happened. With all the cars I own in the past this sensor failure is my first. I tried to find the cause of such a failure on Internet, and all I found was "too much heat". I wonder if there is any DIY things that I can do in the future to lengthen the life of these sensors since the labor and parts cost me $500 this time.

 

[Merkava_4]

Originally Posted By: sifan
I tried to find the cause of such a failure on Internet, and all I found was "too much heat".


A lot of those crankshaft position sensors are down low on the engine where they can get struck by road debris.

 

[ram_man]

Absolutely nothing you can do. It's just a misfortune that could happen to anyone. Just do the maintenance on time that's about all you can do

 

[HTSS_TR]

My 2000 E430 at 120-125k miles had failing crankshaft position sensor without CEL for several weeks, so I didn't what caused the engine died on several occasions, finally CEL went off and the OBD 2 reader pointed to crankshaft position sensor.

The LS400 with more than 380k miles didn't suffer that problem.

 

[Colt45ws]

More often its not so much heat, its debris and water and other stuff that get to them, being on the front of the engine mounted low. Recently, they are getting moved to the back of the engine, sticking down into the bellhousing so they are more protected.

 

[JetStar]

Almost all cam and crank position sensors fall into two catagories. 1.) Variable reluctance which relies on a wound coil to detect the trigger wheel. Typically 2 wires. 2.) Hall effect which is a semiconductor that senses the trigger wheel, also with magnetism. Typically 3 wires minimum. Each type has its own failure mechanisms. For instance, wound coils like to open due to wire breakage where soldered to the termnals if there is inadequate strain relief. Potting can compound the issue due to differences in CTE. In aerospace, its usually not the absolute heat that kills sensors, it's the thermal cycles and vibration that build stress to the point of mechanical failure.

 

[Mr Nice]

Heat and vibration will kill it.

 

[NHGUY]

Time for another NHTSA investigation...what did Toyota know and for how long...

 

[ARCOgraphite]

Everything has a service life - seems about normal from what my co-workers have reported as mean time to failure - my boss just replaced her (2) CPS on her Nissan v6 SUV at 137K miles.

 

[Rick in PA]

I just had to replace my camshaft sensor at 110K miles. Two bolts, one electrical connector, not a bad job. Fortunately, it was flaky and throwing codes (P0340, I think) but still running. It's a hall effect sensor from what I read above.

Reading through parts notes on Rock Auto, one of the sensor manufactures stated they have a life expectancy of ~100K miles.

I think I'm going to look into my crankshaft sensor just to see what's involved...

 

[bowlofturtle]

My 2005 g35 has needed two sensors.

First one at near 70k, the crank sensor gave out. Car stalled, took like 5 tries to start up. Stalled again and fired right back up. Made it home no more issues. I replaced the sensor the following day and called it good. This sensor was mounted on the bottom engine block. No physical obvious damage.

My most recent was cam sensor bank 2. Behind/under the throttle body. At 85k, a month prior the car didn't want to start once but fired up on second try, i didn't think twice. Then a month later, CEL came on, following day the car would just give me problems starting. Stalled once on me. I replaced that sensor and so far so good.

Good thing these sensors are easy to find and $40-50 online. $80-100 in-stores. Most are really easy to find and held on by a 10mm bolt. To me its a normal maintence item nearing 100k, kinda like tie rods. I believe at one point they need to replaced but just wait for them to die.

My maxima just needed a cam sensor recently in the 130k range.

 

[artificialist]

I have never seen a sure way to extend the life of most automotive sensors. It seems like the way they were built at the factory determines life, and replacement ones are often hastily made copies which can be even worse.

Having an oxygen sensor last is determined by oil consumption, how cleanly the engine burns fuel, and the additives to boost octane.

Sometimes you can extend the life of a MAF using specially designed cleaners, but that doesn't always help.

Other times, the sensor is located where it will always encounter road salt. 4 channel ABS brake systems encounter this.

Wiring to the sensor isn't perfect either. When dealing with a Toyota Camry or Lexus ES300, sometimes no matter how much care you put into removing the ABS sensor to install struts or wheel bearings, the cable STILL fails.

From the 1980s to the early 2000s, cam sensors would often be located in the distributor, and if the oil seal failed, it would easily destroy the sensor. Other times, the distributor bushings would fail, causing the rotor to move erratically. When that happened, sometimes the teeth of the distributor ring would collide with a sensor and destroy it.

 

[Donald]

Originally Posted By: sifan
My 2003 Toyota Echo with 127K miles finally left me stranded the very first time since new at a parking lot. Three hours earlier its engine died without warning on a busy interstate highway. I pulled it over to the shoulder immediately and was able to restart the engine with CEL came on. After the replacement of both camshaft and crankshaft position sensors the engine runs like new.

I have diligently upkept my car, but the early warning signs of both failing sensors are also shared by bad spark plugs, clogged fuel injectors, etc. It is very hard to know exactly when to replace these sensors before they fail totally. Just few weeks ago I replaced the plugs, air filter, PCV valve, and ran several Techron treatments consecutively. I could see the improvement in engine performance, but then this happened. With all the cars I own in the past this sensor failure is my first. I tried to find the cause of such a failure on Internet, and all I found was "too much heat". I wonder if there is any DIY things that I can do in the future to lengthen the life of these sensors since the labor and parts cost me $500 this time.



I would not use as much Techron as you have. Follow the label.

 

[CBR.worm]

I had to do a crank position sensor on my FX right around 100k, haven't had to do either on my G35 yet. They seem to be pretty common failure points.

My impression is that some cars will run missing input from one of the sensors, others won't.