Vehicle: 2007 Dodge Caravan, V6-3.3L, VIN R Automatic Transmission
Problem: This vehicle came to the shop because the engine would crank but not start and the MIL was on. The camshaft (CMP) and crankshaft (CKP) sensors had already been replaced but did not fix the problem.
Details: The technician connected a scan tool and pulled DTCs P0335 (CKP sensor circuit signal) and P0340 (CMP sensor circuit signal). The Tech-Assist consultant advised the technician to scope-test the CKP signal wire. There was no signal. Next, the technician checked the Pink/Yellow (Circuit F855) wire for a 5-volt reference voltage at the CKP and CMP. There was only 1-volt at both sensors.
After reviewing the wiring diagram, the Tech-Assist consultant noted that the MAP (Manifold Absolute Pressure) sensor, the TPS (Throttle Positon Sensor), CMP, CKP, AC Pressure sensor and the EGR (Exhaust Gas Recirculation) valve were all on the same circuit. He asked the technician to unplug each sensor one at a time while monitoring the reference signal at the CKP sensor wire.
Confirmed Repair: When the technician unplugged the EGR valve, the 5-volt reference returned to all of the sensors on the circuit. He replaced the EGR valve, cleared the DTCs and the engine started. The problem was fixed.