Diagnosing Cam Position Sensor Issues - HPTuners
Diagnosing Cam Position Sensor Issues - HPTuners In need of some input. I have an early 01/02 8.1 in my 69 blazer. Using yukon xl 8.1 PCM with reworked 5.3 harness. The cam position sensor wiring is different 5.3 vs 8.1 so I swapped a few of the pins around to work with the 8.1 sensor.
5.3 CMP:
[http://www.lt1swap.com/pictures/99_02_schematics/CMP,%20CKP,%20Knock.gif](http://www.lt1swap.com/pictures/99_02_schematics/CMP,%20CKP,%20Knock.gif)
8.1 CMP:
[http://www.lt1swap.com/pictures/fig_6.gif](http://www.lt1swap.com/pictures/fig_6.gif)
My pigtail now matches the 8.1 schematic. Heres my issue, I keep getting codes P0342 and P0343. I was able to start and it ran fine (without any timing related issues).
Recent log had none of these codes and now its throwing them again except, this time, it cranks and wont start.
Also backfiring so it seems that CMP is not working. With the sensor unplugged, engine starts and runs.
Code descriptions:
P0342 - Camshaft Position Sensor A Circuit Low (Bank 1 or single sensor) (Pending)
P0343 - Camshaft Position Sensor A Circuit High (Bank 1 or single sensor) (Pending)
The sensor is a new AC delco sensor and i've verified that wiring is per the 8.1 schematic and I have no loose pins. I have 12v at the 12v reference pin and have logged cam sensor low to high and high to low. Not clear on how these should work but they appear to be a counter of sorts. Both value climb upwards from 0, one shortly after the other.
Any ideas here? Is there a better way to diagnose a bad sensor? Thanks all.
5.3 CMP:
[http://www.lt1swap.com/pictures/99_02_schematics/CMP,%20CKP,%20Knock.gif](http://www.lt1swap.com/pictures/99_02_schematics/CMP,%20CKP,%20Knock.gif)
8.1 CMP:
[http://www.lt1swap.com/pictures/fig_6.gif](http://www.lt1swap.com/pictures/fig_6.gif)
My pigtail now matches the 8.1 schematic. Heres my issue, I keep getting codes P0342 and P0343. I was able to start and it ran fine (without any timing related issues).
Recent log had none of these codes and now its throwing them again except, this time, it cranks and wont start.
Also backfiring so it seems that CMP is not working. With the sensor unplugged, engine starts and runs.
Code descriptions:
P0342 - Camshaft Position Sensor A Circuit Low (Bank 1 or single sensor) (Pending)
P0343 - Camshaft Position Sensor A Circuit High (Bank 1 or single sensor) (Pending)
The sensor is a new AC delco sensor and i've verified that wiring is per the 8.1 schematic and I have no loose pins. I have 12v at the 12v reference pin and have logged cam sensor low to high and high to low. Not clear on how these should work but they appear to be a counter of sorts. Both value climb upwards from 0, one shortly after the other.
Any ideas here? Is there a better way to diagnose a bad sensor? Thanks all.
Teching In
Joined: Mar 2022
Posts: 2
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I am new here. I do not know where to post my issue. I am lost. Here is my video. I have a service engine light. New engine. cam Position Reads High Volts. and cam position sensor reads low volts. it is NOT wiring. It is NOT Sensor. new x4. It is not battery, (new) Please help. I Can not pASS cALI sMOG.
