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Although there are no drivability problem, check engine lights would come and go. Owner menioned he repaced the CMP sensor with an after marke one. I scoped he CMP sensor. Iniial waveform showed a normal 0 to 5V digial waveform. However as i warmed up, waveform showed 3-5.6V and then back to 0 - 5V and back to 3-5.6V !
I reommended for an OEM cmp sensor from he dealer. Waveform now normal 0 to 5V during cold and hot engine. I decided to scope both CMP and CRK sensor just to see if both showed the same characteristic of a good one I found in Picos Library and they did.. Erased the fault codes, drove it around while observing CMP/CKP counter readings, MAF sensor, STFTs averaed 5-8% and O2 sensors on both banks were all good, and all seem fine. After a few times of starting and restarting,check engine lights is back on!
Would appreciae some assstance...thanks.
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Last edit: 2 years 11 months ago by robert.lesaca. Reason: inadvertently posted here...
Any chance the owner bent over one of the CMP reluctor teeth while he was trying to get the CMP sensor out? I've seen it before, and it's an easy thing to do.
I've also seen crank sensors play games on these engines. The latest one had the owner change the CMP three or four times before they gave up. :lol:
Eh, I dunno that they're unusually soft? It more depends on how stuck the sensor was, and how mean the owner got with it.
Normally, the CMP sensor breaks off flush with the timing cover during removal. Owners will try to get something on the broken part to get it out. If the reluctor wheel happens to have a tooth in front of the sensor, you can bend the tooth.
The vehicle did run when I drove it for about 5 minutes. As I stopped at the light, check engine light came on. Did scan and both PO340/341 as well as a new PO430 (B2 3-way cat threshold). Im wondering if this has something to do with the CMP code.
I forgott o menion, owner has another battery connected in parallel to the existing battery. He said he encountered a low battery before and could not start the vehicle, the extra battery in parallel...can this be a factor?
Owner asked if replacing ECM will silve the intermittent problem. I told him I did check CMP and CRK at the ECM as well as low ref, signal and 5 V ref and test showed excellent readings and replacinf ECM is unneccesary. Owner took the chance and according to him the codes went away but a new one appeared that indicated CRK need to be relearned. He drove it several times and code is still there.
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