Camshaft position sensor location

Tiny
PHANTOMSNAKE
  • MEMBER
  • 1997 TOYOTA COROLLA
  • 1.6L
  • 4 CYL
  • 125,000 MILES
My check engine light is on because of my camshaft position sensor and I can't find a video of where my camshaft position sensor on my car listed above is located.
Saturday, July 4th, 2020 AT 11:25 PM

10 Replies

Tiny
STEVE W.
  • MECHANIC
  • 13,413 POSTS
The camshaft position sensor in that car is part of the distributor itself. To replace it you replace the distributor. What is the actual code you have?
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Saturday, July 4th, 2020 AT 11:52 PM
Tiny
PHANTOMSNAKE
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The code is PO340.
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Sunday, July 5th, 2020 AT 1:42 AM
Tiny
STEVE W.
  • MECHANIC
  • 13,413 POSTS
Okay, that is a cam sensor circuit code. It can mean a bad sensor or the wiring or connections in the circuit. There is a simple resistance test that might show you if it's the sensor or elsewhere. There is a 4 pin connector that comes out of the distributor. If you unplug it and use an ohmmeter across the two pins as shown in the first image you should get the following readings. If you do then the issue is more likely in the connector or wiring.
For testing Cold is from 14°F to 122°F and Hot is from 122°F to 212°F

Pickup coil resistance between the terminals
Cold G (+) and G (-) 185 - 275 ohms
Hot G (+) and G (-) 240 - 325 ohms

I would also test the crankshaft position sensor, they are both used by the ECM and there are multiple times when a bad crank sensor has set a cam sensor code because they are compared to each other. This test is shown in the second image, you unplug the connector for it and test the resistance between the two terminals.

Crank position coil resistance between the two terminals
Cold 1630 - 2740 ohms Hot 2065 - 3225 ohms
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Sunday, July 5th, 2020 AT 6:50 PM
Tiny
PHANTOMSNAKE
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Thank you so much. This is very well detailed and I think I got the basic idea about it.
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Sunday, July 5th, 2020 AT 8:44 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,413 POSTS
Any questions just ask. I always test before condemning parts as it saves money in the long run. I've seen and had far too many people say oh we replaced the ECM, these sensors, this part and it still has the problem, only to do some diagnostic work and find it was being caused by a bad ground wire, or a corroded connection.
Could the sensor be bad? Yes, but I'd rather have you test it before spending around $200.00 to replace the distributor.
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Sunday, July 5th, 2020 AT 9:17 PM
Tiny
PHANTOMSNAKE
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  • 6 POSTS
I'm new to using a multi-meter so if I tested the resistance incorrectly please let me know. This is the only multi-meter I had on hand (image 1), and my car was off when I did this.

(Image 2 and 3)
So when I checked the resistance like in the picture I got no resistance but when I tested the bottom ones I had some resistance, results are shown below as well as the cable that's on the distributor I tested:
†(top)Gold pins-no resistance
†(bottom)Silver pins- 00.5 sometimes 00.3-00.8

(Image 4)
But just in case I checked if there was something wrong with my multi-meter and I decided to test the other cable that was connected to it.
And these are the results I got:
top pins 23.8
bottom pins 10.27

(Image 5, 6, and 7)
Then I decided to test what I assume was the cable in the second image as shown below:
So the first test gave me a resistance of 22.5
While the other cable gave me a resistance of 89.5

The last image is a zoom out of where I found the cable.
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Tuesday, July 7th, 2020 AT 8:48 PM
Tiny
STEVE W.
  • MECHANIC
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Okay, it sounds like the crank sensor is okay. The cam sensor however, if you were reading no resistance across the two marked pins the cam position section of the sensor is bad. The repair is a replacement distributor as the individual part is no longer sold. It isn't a hard part to change but you do need a timing light to check the timing.
There is one bolt that clamps the distributor to the cylinder head. Normally you would remove the wires from the cap but as yours is running okay at the moment I would suggest removing the distributor cap from your old one first, leaving the wires in place for now.
Then disconnect the connector you tested and remove the hold down bolt and the distributor will pull out of the head.
To install the replacement you need to set the engine at top dead center on the compression stroke. You do that by removing the spark plug from cylinder number one. Then you put a finger or dowel tightly over the spark plug hole and listen as you turn the engine by hand. As it nears TDC you should hear a hissing sound as the air tries to escape, now gently rotate the engine clockwise until the notch on the balancer lines up with the TDC pointer. Then verify that the slot in the camshaft matches the picture. Next you apply a bit of clean oil to the o-ring on the new part, then rotate the drive on the distributor so that the notch on the drive lug matches the small bar on the housing, those are the items that need to line up marked in the picture. At that point the new distributor should slip into place and you can install the bolt. Now you can use the old cap numbers as a guide and remove the wires from the old cap and place them onto the correct terminals on the new part.
The next step is to verify that it is installed correctly by checking the timing. For that you connect a timing light up and start the engine, if it starts okay then you are close to done, you just need to check that the timing is on 10 degrees before top dead center. If it is, and the CEL goes out, you're finished.
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Tuesday, July 7th, 2020 AT 10:00 PM
Tiny
PHANTOMSNAKE
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Thank you so much again for the help again.
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Tuesday, July 7th, 2020 AT 11:37 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,413 POSTS
You are welcome. Please keep us informed of what happens.
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Wednesday, July 8th, 2020 AT 9:38 AM
Tiny
PHANTOMSNAKE
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Will do.
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Wednesday, July 8th, 2020 AT 9:56 PM

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