Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Hey guys hope all is well! Was wondering if I could get some help on a car I am currently working on (2005 Cadillac cts v 5.7 ) crank, no start. It was brought in for a non functioning fuel level sensor which ended up being a chewed up harness along the fender after doing the diag. I fixed the car up and sure enough the codes cleared out without me having to clear the codes (only had a fuel level sensor voltage code). Only problem is that now it won’t start up, no codes. Fuel pump is priming, and I noticed that when I command the fuel pump on a couple times the obd port looses power and disconnects (also sometimes disconnects when I am cranking the vehicle). Without having to do anything the scanner comes back to reading like nothing after a second or 2. If I prime the injectors individually it starts up for 2-3 seconds then dies out. Sounds like something is pulling to much power causing everything to shut down. Trying to follow a wiring diagram at the moment to try to match the fuel pump to OBD power at the moment but figured I’d ask while I work on it, scanner is reading no codes present. Thanks in advance!
Forgot to mention the tank had been pulled out to check the fuel pumps. Im wondering if a fuel line got pinched and is not allowing fuel through (due to the fact that if I prime the fuel rails and start the vehicle it will stay running with starter fluid). But that wouldn’t explain why the OBD looses signal when cranking or turning on the fuel pump. Sometimes it just randomly disconnect with the igniation key being on at times
Have you verified with a voltage measurement on pin16 of the data link connector that loss of battery voltage is indeed causing the scan tool to disconnect?
Not doubting you but, the tool can disconnect for multiple reasons including poor power, poor ground, network communication issues (and some older cars just do lose communication while cranking, probably not your Cadillac though)
Does the tool power off when this happens, or does it just lose communication with the vehicle?
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