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am reposting this query which I inadvertantly posted on the WELCOME portion...
Although there are no drivability problem except for the check engine lights that come and go,owner mentioned he replaced the CMP sensor with an after market. Every time it will take a longer crank the engine would start and with the check engine lights on. I decided to scope the CMP and as the engine warms up, the waveform would become erratic fluctuating between 3 to 5.6 V and then normalize between 0 to 5V. I recommended a brand new CMP from the dealer. After rescoping the new CMP sensor, waveform was normal all through out reading 0 to 5V squre wave. I then scoped both CMP and CKP sensor to see proper synch. and from the looks of it, it did synch (I will need to recapture the waveform and will forward to this forum). The problem is this : check engine light will still light intermittently despite having no drivability issues. What am I missing?
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