chk engine light question

[hugho]

Just bought my first camry, a "97 which came with a check engine light. I hooked up my code reader and it was a cam sensor code. I popped in a new cam sensor and erased the code and the light came back on after a few sec. It again was the cam sensor code. The car is a 4 cyl with 115K and seems to run great. What gives? what's the next step?

[dc_98_cam]

Check that sensor wire connectors are reasonably clean and making good electrical contact. .... Advise getting a can of spray type electrical contact cleaner ... disassemble connector and use liberally on both sides of connector. ...
Also, inspect sensor wire harness .... not rubbing against anything.

Not much else it could be .... maybe something wrong with the ECU.
Seems like there was only one possible orientation when mounting near the cam gear.

[bigbird]

u may also need to reset the ECU. just unplug the battery for a few mins and then if it comes back on u can rule out the ECU.

[Kep]

OK, I'm not sure just what a cam sensor senses. However, if the sensor and ECU are working properly with no sensor faults, what does a cam sensor error indicate?

Kep

[dc_98_cam]

Originally Posted by Kep

OK, I'm not sure just what a cam sensor senses. However, if the sensor and ECU are working properly with no sensor faults, what does a cam sensor error indicate?

Kep

Think it is a rotational speed or position sensor for the cam gear...
It would be a magnetic sensor, picking up the cam gear teeth as they pass by.

The car drives without it being plugged in, but doesn't have the same performance, and also will have the CEL.

[digmycelica]

Originally Posted by hugho

Just bought my first camry, a "97 which came with a check engine light. I hooked up my code reader and it was a cam sensor code. I popped in a new cam sensor and erased the code and the light came back on after a few sec. It again was the cam sensor code. The car is a 4 cyl with 115K and seems to run great. What gives? what's the next step?

If it's a little sluggish, or idles a little weird, it might be the timing belt was changed and the timing belt is off a tooth on timing. Could be a broken wire in the harness if it's rubbing something, look very close..
Could even be the distributor or the ecu.
what was the code number?

[hugho]

Thanks so much guys for your well considered thoughts. The timing belt was done @ 100K so I guess they could have screwed the alignment up. The code is PO 340. It's not rubbing or abraded anywhere I can see and the contacts look clean. I wonder how many ohms a continuity test of the harness plug would be? I ordered a shop manual which may help. Hugho

[ihartmacz]

Does this engine have a cam position magnet for the sensor to pick up on?

My Buick's 3.8L V6 had one, every once-in-a-while the engine would throw the magnet off the gear.

I don't know if the 5s-fe would have it, but it's worth a check.

[csaxon]

Who did the timing belt? It does sound that it's off a few teeth, it may have slipped. This can set off the 340 code. Crank sensors seldom go bad.

[dc_98_cam]

Originally Posted by ihartmacz

Does this engine have a cam position magnet for the sensor to pick up on?

My Buick's 3.8L V6 had one, every once-in-a-while the engine would throw the magnet off the gear.

I don't know if the 5s-fe would have it, but it's worth a check.

I don't recall seeing any sort of magnet on the cam gear ... It might have been machined into one of the gear teeth though .... not readily apparent that it was there. Unlikely to come loose if there was one.

[bronzemaxell]

Originally Posted by dc_98_cam

I don't recall seeing any sort of magnet on the cam gear ... It might have been machined into one of the gear teeth though .... not readily apparent that it was there. Unlikely to come loose if there was one.

last time i look at the cam gear and crank shaft gear on my 97 camry 2.2L
it has a little flat metal at the gear ring,
i think the cam gear sensor has magnetic sensor to detect that flat metal on the gear as it rotates and differentiate that to the rest of the gear teeth, to sense the revolution of the gear.

while i was changing timing belt, i forgot to plug the crank sensor wire back on,
the engine just crank, but won't startup.
i haven't try to unplug the cam sensor wire, but i would imagine it will does the same thing.

[digmycelica]

Originally Posted by hugho

Thanks so much guys for your well considered thoughts. The timing belt was done @ 100K so I guess they could have screwed the alignment up. The code is PO 340. It's not rubbing or abraded anywhere I can see and the contacts look clean. I wonder how many ohms a continuity test of the harness plug would be? I ordered a shop manual which may help. Hugho

Disconnect camshaft position sensor connector
Using an ohmmeter, measure the resistance between terminals of the sensor.
cold 845 - 1400 ohms
hot 1060 - 1645 ohms
If in specs, check connector or harness for broken wire.

Camshaft position sensor (G signal) consist of signal plate and pick up coil.
The G signal plate has one tooth on its outer circumference and is mounted on the exhaust camshaft. When the camshafts rotate, the protrusion on the signal plate and the air gap on the pick up coil change, causing fluctuations in the magnetic field and generating an electromotive force in the pick up coil. The NE signal plate has 34 teeth and is mounted on the crankshaft. The NE signal sensor generates 34 signals for every engine revolution. The ECM detects the standard crankshaft angle based on the G signals and the actual crankshaft angle and the engine speed by the NE signals.

[hugho]

Thanks again especially recent posts. I checked the Ohms on the sensor and it was on spec, 1120 ohms so that isn't the problem. I just returned from a long road trip with 2 friends and driving conservatively almost all hwy mileage returned only 28.4 mpg. I have never owned a toyota before and I really expected better mpg from an itsy bitsy 4 banger. We live at 6000+ feet in WY but this mileage should be better shouldn't it? I replaced my 97 Pontiac Bonneville with this Camry after the bonnie was totalled and T Boned. It had a 3.8 L engine, weighed over 600 lbs more and had about 180 hp and I averaged 30 mpg. It also had an automagic transmission. I'm wondering if the cam sensor code is the cause of this. I bought a proscan setup for my laptop and didn't turn up anything amiss. What's next?

[dc_98_cam]

MPG sounds slightly low .... even with 3 people you ought to get 30+mpg.
I would be curious as to whether your timing is exactly on the spot ...
If you remove the upper timing belt cover, you can line up the crank pulley mark, and then inspect the small hole in the cam pulley, to see if the cam pulley is lined up with the correct mark.
If you haven't done this before, maybe somebody has a picture of the correct cam gear position. .... That's what's important. .....Also, I found that for the timing belt to be correctly installed, you should observe 'no slack' in the upper timing belt on either side of the cam gear .... if that makes sense ....You can have a small amount of deflection on either side of the cam gear, but it should be symmetric, and no obvious inequality in slack or looseness on one side or the other of the belt. If you do see obvious slack in the belt, you will have to remove the belt from the cam gear, and readjust it for symmetry. ....
Also, there is a specific technique for the final tightening procedure of the upper idler pulley ..... see repair manual, but the most important thing is the symmetry and uniformity of the timing belt.

[digmycelica]

Originally Posted by hugho

Thanks again especially recent posts. I checked the Ohms on the sensor and it was on spec, 1120 ohms so that isn't the problem. I just returned from a long road trip with 2 friends and driving conservatively almost all hwy mileage returned only 28.4 mpg. I have never owned a toyota before and I really expected better mpg from an itsy bitsy 4 banger. We live at 6000+ feet in WY but this mileage should be better shouldn't it? I replaced my 97 Pontiac Bonneville with this Camry after the bonnie was totalled and T Boned. It had a 3.8 L engine, weighed over 600 lbs more and had about 180 hp and I averaged 30 mpg. It also had an automagic transmission. I'm wondering if the cam sensor code is the cause of this. I bought a proscan setup for my laptop and didn't turn up anything amiss. What's next?

Hugho,
I'd like to say that I think the mileage is normal if this is an automatic. If it's a manual you should be getting around 34 on a trip. You are correct that the 3800 engine will average 30 -31 on a trip . Those cars were geared perfectly and are hard to beat for comfort and mileage. I had a Honda Accord with a automatic and it would only get 27 on a trip. Heck , My Lincoln Towncar gets 24 so sometimes smaller is not always better. It all depends on how it's geared and how much of a lead foot you have. I think no matter what you do It's not going to get as good as the 3800. But good luck trying!