Camshaft sensor keeps failing | Ford Escort Owners Association (FEOA)

Camshaft sensor keeps failing

Discussion in '2nd Gen 1991-1996 1.9L SOHC' started by db1793, Oct 20, 2018.

  1. db1793

    db1793 FEOA Member

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    Recently, my check engine light came on after starting the car. Then it would go off after driving for a bit. Drove it on the expressway the day this started, and it never came on. Since then, it keeps coming on and off while driving. I checked the codes and it shows up as the camshaft position sensor. We've owned this car since 2005 and I have had to change this sensor at least twice already. It was last replaced in July 2016 (23,000 miles ago) with a BWD CSS105 sensor. I find it hard that these sensors keep failing when they don't have any moving parts. Are the aftermarket ones just made that cheap? Has anyone else had these sensors fail repeatedly? (I also just noticed that BWD doesn't list CSS105 anymore, the new part number is CSS1535.)

    I thought since the check engine light was only coming on intermittently, that maybe it was the sensor connector, however, the connector doesn't have too much play in it, and looks fine to me. I've noticed that the check engine light seems to be related to RPM. Driving around town or idling, light comes on. Drive on the highway and keep the RPMS constantly above 2000 and it goes off. Does that sound typical of these sensors when failing?
  2. denisond3

    denisond3 Moderator Staff Member

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    As to reliability, I have never had one fail that I know of. I have tried driving around the block with the connector pulled off, and couldnt tell a difference in how it ran.

    So maybe it is an issue with the wiring, but not the sensor, and not the connector right by it. One of our members has theorized that at higher rpms, the computer doesnt use the input from the camshaft position sensor at all.

    You might want to ensure that the two large connectors by the passenger side strut tower are fully seated. I think the wiring for the cam position sensor goes through them, as does the signals for firing the injectors.
  3. zzyzzx

    zzyzzx FEOA Member

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    I also think that it is an intermittent wiring problem. My first choice would be the connector that goes into the sensor has some sort of issue, like dirt, corrosion, or it's loose.
  4. marclar

    marclar Moderator Staff Member

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    what year is the car?
  5. db1793

    db1793 FEOA Member

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    Car is 1994 1.9 Auto.

    I checked the 2 large connectors, they both appeared to be securely connected. Sensor plug connect and wiring looks to be in good shape too.
  6. zzyzzx

    zzyzzx FEOA Member

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    How did you check the sensor plug?
  7. zzyzzx

    zzyzzx FEOA Member

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    Exactly how are you checking the actual sensor?
  8. db1793

    db1793 FEOA Member

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    Visual inspection. Connection doesn't appear to be in bad shape. Wiring looks good. Removed the connection and cleaned with Electronic cleaner.

    I'm not. Is there an actual testing procedure? Is there a spec for what the resistance across the terminals should be?


    It's now pretty much at the point the Check Engine light is constantly on. This is pretty much what happened the last time too. Light came on intermittently at first, eventually getting to the point where it's just always on. Car runs fine most of the time, but occasionally idles rough, and will occasionally bog down when accelerating from a stop. Hasn't stalled yet though.
  9. denisond3

    denisond3 Moderator Staff Member

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    I think the sensor is just a small diameter magnet with a wire coil wrapped around it. So the signal the computer gets would be an alternating wave, with the pulse corresponding to the moment when the camshaft rotates to a particular angle. (By contrast, the Crankshaft Position Sensor is the same except provides a stream of pulses, 35 of them per one turn of the crankshaft, with the missing tooth on the tone ring resulting in one missing pulse, so the computer can tell what the crankshaft position is). The computer reads the signals and probably inputs sharper pulses to the processor on the computer board. I would wonder if that circuit on the computer board had failed.
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  10. zzyzzx

    zzyzzx FEOA Member

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    Yeah, but did you check the connection on the inside part where it plugs into the sensor AND on the other end where it plugs into (whatever it plugs into, probably the cars computer).



    I would have to look this up, but off the top of my head, I would say at the very least check to make sure that it isn't an open circuit in the sensor itself. Take an ohms reading and post it here.
  11. denisond3

    denisond3 Moderator Staff Member

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    Getting to the connector on the computer involves taking off a panel on the passenger side of the bottom/front part of the console. What you hope you dont find is any antifreeze on the computer - from a leaking heater core. (Been there, done that.)
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  12. db1793

    db1793 FEOA Member

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    Was able to get a resistance reading on it. Ohmmeter was reading 0.4 Megaohms. Then i took an AC voltage test with the engine running. At idle, it produced a little less than 1 volt and increased with RPM.
  13. zzyzzx

    zzyzzx FEOA Member

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    According to the shop manual, resistance should be between 300 and 750 ohms. You are measuring 400000 ohms. You should check that, and compare it to any of your old ones if you still happen to still have them. I have to wonder if you did it wrong, and it's really 400 ohms. Also, the test says that with the engine running, the AC volts should vary with RPM.
  14. Intuit

    Intuit FEOA Member

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    The clip that held my sensor's wire harness on broke. Well over a decade of heat cycling had made the plastics brittle. I had wedged some stiff wire in the harness to keep it plugged in. Never had to touch it afterward... to my surprise.
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  15. db1793

    db1793 FEOA Member

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    The sensor was definitely shot. I took another another resistance check, and it was 0.5 Megaohms. Brought the old one back to the store with my original receipt, and got a replacement for free. New sensor is a Standard Brand. Checked the resistance of the new one and it was 332 ohms. Got it installed and the car runs fine again, no check engine light. Pretty disappointed that these sensors have had such a high failure rate.
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  16. marclar

    marclar Moderator Staff Member

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    should be in the 350ohm range iirc. its unfortunate for sure, i work in automotive for a living, and we see this all the time. last week, i went through 5 alternators from oriley before i got one that worked. all reman in mexico by Chinese parts.
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  17. zzyzzx

    zzyzzx FEOA Member

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    How much convincing did it take to get this new one for free, and did you take an ohms reading on the new one before you left the store, or at least the parking lot?



    Remember that YOU are the quality control! You should be OK with Standard branded parts, I should think.

    Obligatory gloating because my advice helped out (pats self on back).
    Last edited: Oct 30, 2018
  18. marclar

    marclar Moderator Staff Member

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    I just put a p/s pump in a pilot that doesnt work.. case and point lol
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  19. Intuit

    Intuit FEOA Member

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    That I've seen over the decades, the OEM sensors didn't. As I've come to learn, aftermarket anything is another matter. I used to believe in "preventative maintenance" only to later find out that it was nearly always "causal repair". Eventually my preventative maintenance was limited to fluids, tires and anything that is consistently noisy. It ain't breaking, I ain't fix'n it.
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  20. db1793

    db1793 FEOA Member

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    I called O'reilly prior to disassembling and the worker told me it was covered. No hassle. So when I brought it in, I said, that I called earlier and they said they would replace it for free. The worker in the store had no problem with that. However, it became more of an issue that the part number from the one I had was different than the one currently listed. But the real issue was that they no longer stocked the new BWD part at all, and couldn't order it. The worker than said she would let me have a different brand one for free.

    I then proceeded to check the new one with my ohmmeter in the car in the parking lot.

    Seems to be the case on these cam sensors. I think the original one last 10 years, the 2nd one lasted 6ish years, and the 3rd lasted just over 2 years.
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