Chrysler 2007 Pacifica P0203 and P0660 Fault Diagnosis - Cylinder 3 Injector and Intake Manifold Tuning Valve Issues
I recently encountered two diagnostic trouble codes on my 2007 Chrysler Pacifica: P0203 (Injector Circuit Open - Cylinder #3) and P0660 (Intake Manifold Tuning Valve Circuit Open). Initially, I had a P0303 code indicating a misfire in cylinder 3, which led me to replace all spark plugs and valve seat seals. After the repairs, symptoms improved temporarily, but the next day the new codes appeared. I'm now unsure whether these codes point to a faulty injector or a problem with the intake manifold tuning valve (MTV). I suspect that replacing the solenoid for cylinder #3 might resolve the issue, but I'd like confirmation on what each code specifically indicates and how to properly diagnose them without causing further damage. Could someone provide guidance on testing these components step-by-step? Specifically, I'm looking for instructions on checking voltage at the injector wiring (KOEO), verifying the MTV connection, and confirming the relay functionality—especially since it shares a fuse with the AC system.
EDIT: The following advice applies only if you know the exact engine type—answers may be generic otherwise. To diagnose the P0203 injector circuit open issue: - Unplug the #3 fuel injector and perform a KOEO (Key On, Engine Off) test. - Check for 12 volts on one wire; the other wire should show no voltage and not be grounded. For the P0660 intake manifold tuning valve (MTV) issue: - Ensure the MTV is securely plugged in. - Test the relay—note that it shares the same fuse as the AC system. Confirm that the AC clutch operates normally. - If the AC works, try swapping the relay to verify if it's faulty. A bad relay can cause both the MTV and AC issues.