Intermittent Dodge Ram 1500

I received a call on a 2003 Dodge Ram 1500 with an intermittent P0339 code for crankshaft position (CKP) sensor signal. Talking with the technician, I found out another shop had replaced the engine. The customer said it had never run right after that and kept setting the CKP sensor code.

The tech had replaced the CKP and camshaft position (CMP) sensors, trying to eliminate the problem, but it didn’t change a thing. He said the sensors looked like they were new so the original shop must have replaced them trying to solve this problem. But he replaced them, just in case.

I suggested that he lab scope the CKP and CMP and compare them to normal patterns. This way we could tell if it was a sensor problem or a sync issue. I sent him copies of normal patterns. After lab scoping the sensors he called back and said the CKP patterns didn’t look like the ones I had faxed. When I asked if it was an OEM sensor or an aftermarket, he said aftermarket. I suggested trying another sensor just in case it was a bad one. He called back and said even with the new sensor it looked the same.

He emailed the images to me and the CKP pattern didn’t match. He told me that when he replaced the CKP it looked like the sensor had some scratches on the end. I told him to look at the CKP tone wheel to see if there was any damage. He said it looked good with a flashlight. As we were talking I learned that this engine wasn’t replaced, it was rebuilt by shop No. 1. Since then, it had been taken to two dealers and five other shops in the past six months!

I told the tech if the tone wheel looked good maybe the aftermarket sensor was a little longer than the OEM because of the scratches on the end, and that he might want to try an OEM sensor. After installing the OEM sensor, he had the same patterns. I told him if the wiring was good and it had a new sensor, then he needed to go back and really check out the CKP tone ring with a bore scope. I got a call back followed by an email with a picture of a damaged tone wheel for the CKP. When the engine was originally rebuilt, shop No. 1 must have damaged the tone wheel, causing it to hit and damage the CKP sensor. So the tone wheel was the problem.

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