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Crankshaft Sensor

6K views 9 replies 5 participants last post by  sonata0 
#1 ·
Hello,

I am having some major problems with the crankshaft sensor in my 02 Sonata (2.4 auto). Long story short, a couple months ago the car quit running and wouldn't restart. It was towed to the mechanics, where he got a code for the crank sensor, which he replaced and also changed the timing belt while he was in there. The car ran fine for a few days, then started acting like it would stall. After a week, it did. Towed back to mechanics, retrieved the crank sensor code again, he replaced it again. The car ran for 2 days. Still showing the crank sensor code, the mech suggested the problem must be in the ECU, which we replaced, causing the car to run for 5 minutes before dying yet again.

Any suggestions as to what would cause the crankshaft sensor to keep going bad on me? I did a search, the only thing I found suggested a bent tone ring. Suggestions?

Thanks
 
#2 ·
More than likely it's not the ECU. Has your mechanic ever replaced the crankshaft blade at the same time he replaced the crank sensor? It's the metal plate that the crank sensor actually "reads", and it's normally flat. However, if it is bent even the slightest bit, or wobbles at all, it will strike the crank sensor and damage it, and the symptoms will be similar to what you are describing. You can't always look at a crank plate and tell if it's bent because the crank sensor is positioned just a hair away from it, and it doesn't take much of a bend to cause damage. Any time we replace a crank sensor we also replace the blade. At a cost of around $6 or so, it's cheap insurance compared to the cost of a crank sensor.
 
#4 ·
Dear Dark,

Absolutely! Concur with Lil Bean. The 2.4 liter has an inner balance shaft belt that will damage the blade and the crank sensor if it either snaps, or starts to shed rubber pieces prior to failure.

say, did the mechanic replace the inner balance shaft belt when he replaced the timing belt??? These must be replaced at the same time.

Byron
 
#5 ·
No mention was ever made of an inner balance belt. The timing belt did not fail, as no teeth were missing, however some pieces were coming off from the sides of the teeth, could one of these pieces have damaged the crank sensor or crank blade? I did have the mechanic replace the timing belt when he was "fixing" the car's crankshaft sensor.

Out of curiosity, is this blade fairly easy to get at/change? I just paid the mechanic $700+ to fix the car. It is still not running, and he refuses to spend any more time working on it. Just hoping that maybe I could replace the crank sensor and blade myself.

Thanks to all who replied to my post.
 
#6 ·
QUOTE (DarkKnight73 @ Dec 11 2008, 10:15 PM) index.php?act=findpost&pid=205459
No mention was ever made of an inner balance belt. The timing belt did not fail, as no teeth were missing, however some pieces were coming off from the sides of the teeth, could one of these pieces have damaged the crank sensor or crank blade? I did have the mechanic replace the timing belt when he was "fixing" the car's crankshaft sensor.

Out of curiosity, is this blade fairly easy to get at/change? I just paid the mechanic $700+ to fix the car. It is still not running, and he refuses to spend any more time working on it. Just hoping that maybe I could replace the crank sensor and blade myself.

Thanks to all who replied to my post.

Do you have a HMAservice.com account? Go get one, they are free. An invaluable source for finding stuff that is wrong with the car. Also, if you plan on keeping your car for many more miles, invest in a shop manual. They are on ebay for $30 or less.

Chris
 
#7 ·
Dear DarkKnight,

Yes, your mechanic has screwed you. The inner balance belt turns the balance shaft on the 2.4 liter at twice the engine rpm, which nulls out the inherent vibrations in a 4 cylinder engine larger than 2 liter. Ever wonder why you don't see 3 liter 4 cylinder engines? There is an inherent engine harmonic that can not be controlled above 2.5 liters.

The inner balance shaft belt is a pain to get to...you have to remove everything in the way including the timing belt. If the innner belt fails, you will immediately notice because above 40 mph the engine vibration about bounces the car in the air off the road <School of hard knocks>. And the strain of the vibration on the timing belt will cause that to snap.

You need to replace the inner belt, and it will cost as much as a timing belt replacement because you have to remove everything to get to it.

And the little pieces of rubber that had shed from your timing belt could have caused the blade to get damaged. Think of the closed space behind the black plastic timing covers as a small wind tunnel. Imagine throwing a handful of ruber chunks into a wind tunnel. If your mechanic was really sloppy, the chunks likely are still in there.

Byron
 
#8 ·
^^^^^^ Yes, I agree with everything he said. Couldn't have said it better myself.

Every timing belt change on a previous generation 2.4L (not the new 2.4 that's in the 06-up Sonata) should also include a balance belt change, without question.

This is definately where going to the dealer is a plus, because they know info like this and most private shops do not. Also, if you paid $700 for a timing belt change, you got robbed. I guarantee you could have gone to just about any Hyundai dealer and gotten it done cheaper (crank plate and sensor would be about another $90-95 in parts) and it would have been done right the first time. Here we only charge $399 for a 4 cyl timing belt change.

I'm sorry, but I think that now you are looking at practically paying the same labor all over again to do something that should have been done the first time.
 
#9 ·
Hi all,

Finally got the issues resolved with my Sonata. As expected, the goofball mechanic I had been using had installed the crankshaft sensor incorrectly, and it was rubbing on the timing belt which wore out the sensors. I am very thankful that the sensor did not break the timing belt, as we would have had to write off the car. For the fix we had the car towed out of town (my town hasn't had a Hyundai dealer since the 80's) and they had it all fixed up within a couple days. They were more expensive, but they actually fixed the problem!

When we approached the first mechanic about reimbursement, he got all defensive and said he would only refund us the cost of the crank sensor, even though we thought some labour should have been refunded too since he did not finish the job we paid him to do. Anyhow, at least the car is running well. Now we have to decide what to do with it, since the first mechanic told us the car was basically unfixable and having been without a car for 3 months we had to purchase another one (09 Montana - what a great van!). I am unsure whether to sell the Sonata, or keep it for a backup car/winter beater since it is worth very little.

Thanks for all the responses and suggestions!
 
#10 ·
I have a 2004 Sonata 4 cylinder and it immediately chews up the CPS after being replaced. Mechanic says the wheel exploded in the engine and that engine needs rebuilt. Also, is it hard and does it take long to replace a CPS? It was replaced twice chewing it up right away. It ran good for a minute then started acting up again each time.
 
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