Leaderboard

Since the failure appears to be isolated to #4 (and is independent of injector or coil installed), perhaps there is an issue with the harness going from PCM (Power Control Module) to injectors. The CMax Service manual for DTC P0201 calls for harness pinpoint testing as follows (cut & paste from service manual does not work well, so sorry for poor formatting below) : DTC P0201: CYLINDER 1 INJECTOR A CIRCUIT/OPEN DTC P0201: CYLINDER 1 INJECTOR A CIRCUIT/OPEN Description: This DTC sets when the fuel injector circuitry is inoperative. Possible Causes: INJ1 circuit open VPWR circuit open Damaged fuel injector Diagnostic Aids: The INJ1F PID is YES. Application Key On Engine Off Key On Engine Running Continuous Memory All GO to PINPOINT TEST KG . This pinpoint test is intended to diagnose the following: fuel injector(s) (9F593) harness circuits: VPWR and INJ 1 through 4 powertrain control module (PCM) (12A650) Fig. 76: Identifying Fuel Injector Connector Courtesy of FORD MOTOR CO. / Fig. 77: Identifying Powertrain Control Module (PCM) Connector (128 Pin) Courtesy of FORD MOTOR CO. TEST PROCEDURE KG1 CHECK THE VPWR CIRCUIT FOR AN OPEN NOTE: Disconnect the suspect fuel injector harness connector. Only the suspect injector needs to be diagnosed. Ignition OFF. Fuel Injector connector disconnected. Ignition ON, engine OFF. Measure the voltage between: (+) Suspect Injector Solenoid Connector, Harness Side (-) VPWR Ground Is the voltage greater than 10.5 V? Yes No GO to KG2 . REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test. KG2 CHECK THE INJ CIRCUIT FOR AN OPEN Ignition OFF. PCM connector disconnected. Measure the resistance between: (+) Suspect Injector Solenoid Connector, Harness Side (-) PCM Connector, Harness Side INJ INJ Is the resistance less than 5 ohms? Yes No GO to KG3 . REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test. KG3 CHECK THE INJ CIRCUIT FOR A SHORT TO GROUND / Measure the resistance between: (+) Suspect Injector Solenoid Connector, Harness Side (-) INJ Ground Is the resistance greater than 10K ohms? Yes No GO to KG4 . REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. KG4 CHECK THE INJ CIRCUIT FOR A SHORT TO VOLTAGE Ignition ON, engine OFF. Measure the voltage between: (+) Suspect Injector Solenoid Connector, Harness Side (-) INJ Ground Is any voltage present? Yes No REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. GO to KG5 . KG5 CHECK THE RESISTANCE OF THE FUEL INJECTOR Ignition OFF. Measure the resistance between: (+) Suspect Injector Solenoid Connector, Component Side (-) Suspect Injector Solenoid Connector, Component Side INJ VPWR Is the resistance between 11 - 18 ohms? Yes No GO to KG6 . INSTALL a new fuel injector. REFER to the appropriate Fuel Charging and Controls article. RESET the keep alive memory (KAM). REFER to DIAGNOSTIC MONITORING TEST RESULTS MODE 6 . REPEAT the self-test. KG6 CHECK THE FUNCTIONALITY OF THE INJ CIRCUIT PCM connector connected. Ignition ON, engine OFF. Connect a non-powered test lamp between: Point A Suspect Injector Solenoid Connector, Harness Side Point B Suspect Injector Solenoid Connector, Harness Side VPWR INJ Is the test lamp blinking? Yes No GO to KG7 . GO to KG8. KG7 CARRY OUT A THOROUGH WIGGLE TEST ON THE FUEL INJECTOR HARNESS Ignition OFF. Fuel Injector connector connected. Ignition ON, engine running. / Engine at normal operating temperature. Access the PCM and monitor the INJ_F (MODE) PID. Wiggle, shake, and bend small sections of the wiring harness while working from the fuel injector to the PCM. Are any injector values fluctuating in and out of range? Yes No ISOLATE the concern and REPAIR as necessary. Clear the PCM DTCs. REPEAT the self-test. Unable to duplicate or identify the concern at this time. GO to PINPOINT TEST Z. KG8 CHECK FOR CORRECT PCM OPERATION Disconnect all the PCM connectors. Visually inspect for: pushed out pins corrosion Connect all the PCM connectors and make sure they seat correctly. Carry out the PCM self-test. Verify the concern is still present. Is the concern still present? Yes No INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) , Programming the VID Block for a Replacement PCM. The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

Forgot to add this to my post, but this is also a very good item to check. This vehicle as well as most modern ones do have separate coils per spark plug and it is not uncommon for them to occasionally go bad. An easy check without a full on Ford IDS scantool is to clear the misfire codes and swap coils between the reported 'bad' one per the misfire code to another cylinder. If the misfire code follows the coil to the new cylinder, you have your problem. If the misfire position stays, it is something else still tied to that cylinder. Spark plug at best but could be a deeper issue. Also please ensure everything is fully seated and connected when doing this work.