Starting System: Overview — Ford Flex I (2008-2013)

Principles of Operation

The starting system is electronically controlled by the Passive Anti-Theft System (PATS) feature in the Instrument Cluster (IC). The PATS recognizes the correct electronically coded ignition key and signals the PCM to provide a ground for the starter relay. The starting system uses a Transmission Range (TR) sensor located in the transmission. The TR sensor opens/closes a set of 4 switches that are monitored by the PCM to determine the position of the manual lever (P, R, N, D, L). The TR sensor prevents operation of the starter motor, unless NEUTRAL or PARK is selected, and sends a signal to the PCM to start the vehicle. After the PCM One-Touch Integrated Start (OTIS) feature takes over (this feature assists in starting the engine), the customer is no longer in the loop after the initial crank request, the customer may release the key to the RUN position and the PCM provides voltage to the starter relay. The energized relay provides voltage to the starter solenoid with the key in the START position, thereby allowing the starter motor to activate.

Normal Operation

Under normal operation, constant power is supplied to the starter motor relay on circuit SBB10 (YE/RD). When the ignition switch is turned in the START position and held, with the vehicle in PARK or NEUTRAL, power flows to the starter motor relay through CE336 (GN/WH). A ground is supplied through circuit CDC12 (YE) from the PCM causing the starter motor relay coil to energize and the relay contacts close. This allows power to be supplied from the starter motor relay contacts which then flows through circuit CDC25 (BN/GN) to the starter solenoid. The solenoid is grounded at the starter motor. Energizing the starter solenoid will engage the starter drive into the ring gear and closes the solenoid contacts, allowing power directly from the battery through circuit SDC02 (RD) to the starter motor to start the engine.

This pinpoint test is intended to diagnose the following

Battery
Anti-theft system
Starter relay
Ignition switch
Circuitry
PCM
Start diode

Scheme 1

Scheme 1: PINPOINT TEST A: THE ENGINE DOES NOT CRANK

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A1 CHECK THE BATTERY Check the battery condition and state of charge. Refer to Diagnosis and Testing in «BATTERY, MOUNTING AND CABLES»(ref-372793) . Is the battery OK? Yes: GO to A2 . No: CHARGE or INSTALL a new battery as necessary. Refer to «BATTERY, MOUNTING AND CABLES»(ref-372793) . TEST the system for normal operation.
A2 CHECK PCM FOR DTCs Using the DTCs retrieved in Inspection and Verification, check for PCM DTCs. Were any PCM DTCs retrieved? Yes: If PCM DTC P1260 is retrieved, Refer to «ANTI-THEFT - PASSIVE ANTI-THEFT SYSTEM (PATS)»(ref-372795) . All other PCM DTCs, REFER to «INTRODUCTION - GASOLINE MODELS»(ref-355661) . No: GO to A3 .
A3 CHECK THE AUTOMATIC TR SENSOR Enter the following diagnostic mode on the scan tool: DataLogger - PCM. While observing the TR sensor PID, place the vehicle in PARK and NEUTRAL. Does the PID match the gear selection? Yes: GO to A4 . No: GO to the appropriate automatic transmission section to diagnose the TR sensor.
A4 CHECK THE STARTER MOTOR CONTROL OUTPUT DETECTED (SMC_MON) PID Enter the following diagnostic mode on the scan tool: DataLogger - PCM. Monitor the SMC_MON PID with the ignition switch in the START position. Does the PID change from OFF to ON? Yes: GO to A5 . No: GO to A12 .
A5 CHECK THE STARTER MOTOR RELAY ENABLE (STRT_RLY) PID Enter the following diagnostic mode on the scan tool: DataLogger - PCM. Monitor the STRT_RLY PID with the ignition switch in the START position. Does the PID change from DISABLED to ENABLED? Yes: GO to A6 . No: GO to A23 .
A6 CHECK STARTER MOTOR RELAY POWER NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector. Ignition OFF. Disconnect: Starter Motor Relay. Measure the voltage between Battery Junction Box (BJB) starter relay pin 5, circuit SBB10 (YE/RD), harness side and ground. Is the voltage greater than 10 volts? Yes: GO to A7 . No: VERIFY BJB fuse 10 (30A) is OK. If OK, REPAIR circuit SBB10 (YE/RD). TEST the system for normal operation. If not OK, REFER to the «SYSTEM WIRING DIAGRAMS»(ref-360982) to identify the possible causes of the circuit short.
A7 CHECK THE BATTERY GROUND CABLE Measure the voltage between the positive battery post and the battery ground cable connection at the engine. Is the voltage greater than 10 volts? Yes: GO to A8 . No: INSTALL a new battery ground cable. Refer to «BATTERY, MOUNTING AND CABLES»(ref-372793) . TEST the system for normal operation.
A8 CHECK THE STARTER MOTOR GROUND Measure the voltage between the positive battery post and the starter motor case. Is the voltage greater than 10 volts? Yes: GO to A9 . No: CLEAN the starter motor mounting flange and MAKE SURE the starter motor is correctly mounted. TEST the system for normal operation.
A9 CHECK THE POWER SUPPLY TO THE STARTER MOTOR Measure the voltage between starter motor C197A, circuit SDC02 (RD) and ground. Is the voltage greater than 10 volts? Yes: GO to A10 . No: INSTALL a new positive battery cable. Refer to «BATTERY, MOUNTING AND CABLES»(ref-372793) . TEST the system for normal operation.
A10 CHECK THE STARTER MOTOR B-PIN Connect one end of a fused jumper wire to starter motor solenoid 197A, circuit SDC02 (RD). Momentarily connect the other end of the jumper to starter motor C197B, circuit CDC25 (BN/GN). Did the starter motor engage and the engine crank? Yes: GO to A11 . No: INSTALL a new starter motor. REFER to «STARTER MOTOR»(ref-372803-S14409009632010093000000) . TEST the system for normal operation.
A11 CHECK THE CIRCUIT TO THE STARTER MOTOR Ignition OFF. Disconnect: Starter Motor Solenoid C197B. Measure the resistance between starter motor solenoid S-terminal C197B, circuit CDC25 (BN/GN), harness side and the BJB starter motor relay pin 3, circuit CDC25 (BN/GN), harness side. Is the resistance less than 5 ohms? Yes: INSTALL a new starter motor relay. TEST the system for normal operation. No: REPAIR circuit CDC25 (BN/GN). TEST the system for normal operation.
A12 CHECK STARTER MOTOR RELAY POWER NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector. Ignition OFF. Disconnect: Starter Motor Relay. Measure the voltage between BJB starter relay pin 5, circuit SBB10 (YE/RD), harness side and ground. Is the voltage greater than 10 volts? Yes: GO to A13 . No: VERIFY BJB fuse 10 (30A) is OK. If OK, REPAIR circuit SBB10 (YE/RD). TEST the system for normal operation. If not OK, REFER to the «SYSTEM WIRING DIAGRAMS»(ref-360982) to identify the possible causes of the circuit short.
A13 CHECK THE STARTER MOTOR RELAY Carry out the Starter Motor Relay Component Test. Refer to «COMPONENT TESTING»(ref-357210) for component testing. Did the starter motor relay pass the component test? Yes: GO to A14 . No: INSTALL a new starter motor relay. TEST the system for normal operation.
A14 CHECK THE START DIODE Disconnect: Start Diode. Check the start diode for an open or shorted condition. Is the start diode OK? Yes: GO to A15 . No: INSTALL a new start diode. TEST the system for normal operation.
A15 CHECK THE START SIGNAL TO THE STARTER MOTOR RELAY Measure the voltage between the BJB starter motor relay pin 1, circuit CE336 (GN/WH), harness side and ground with the ignition switch in the START position. Is the voltage greater than 10 volts? Yes: For 3.5L vehicles, GO to A19 . For 3.5L Gasoline Turbocharged Direct Injection (GTDI) vehicles, GO to A21 . No: GO to A16 .
A16 CHECK CIRCUIT CE336 (GN/WH) FOR AN OPEN BETWEEN START DIODE AND STARTER RELAY Measure the resistance between the start diode, circuit CE336 (GN/WH), harness side and BJB starter motor relay pin 1, circuit CE336 (GN/WH), harness side. Is the resistance less than 5 ohms? Yes: GO to A17 . No: REPAIR circuit CE336 (GN/WH) for an open. TEST the system for normal operation.
A17 CHECK CIRCUIT SBP27 (BU/RD) FOR VOLTAGE Connect: Start Diode. Connect: Starter Relay. Disconnect: Ignition Switch C250. Measure the voltage between ignition switch C250-4, circuit SBP27 (BU/RD), harness side and ground. Is the voltage greater than 10 volts? Yes: GO to A18 . No: VERIFY Smart Junction Box (SJB) fuse 27 (20A) is OK. If OK, REPAIR circuit SBP27 (BU/RD). TEST the system for normal operation. If not OK, REFER to the «SYSTEM WIRING DIAGRAMS»(ref-360982) to identify the possible causes of the circuit short.
A18 CHECK THE IGNITION SWITCH Carry out the Ignition Switch Component Test. Refer to «COMPONENT TESTING»(ref-357210) for component testing. Did the ignition switch pass the component test? Yes: REPAIR circuit CDC35 (BU/WH) for an open. TEST the system for normal operation. No: INSTALL a new ignition switch. Refer to «STEERING COLUMN SWITCHES»(ref-372776) . TEST the system for normal operation.
A19 CHECK CIRCUIT CDC35 (BU/WH) FOR AN OPEN Ignition OFF. Connect: Starter Motor Relay. Disconnect: PCM C175B. Disconnect: Start Diode. Measure the resistance between the start diode cell, circuit CDC35 (BU/WH), harness side and PCM C175B-9, circuit CDC35 (BU/WH), harness side. Is the resistance less than 5 ohms? Yes: GO to A20 . No: REPAIR circuit CDC35 (BU/WH) for an open. TEST the system for normal operation.
A20 CHECK THE CIRCUIT CE336 (GN/WH) BETWEEN THE BJB AND THE PCM Ignition OFF. Disconnect: PCM C175B. Measure the resistance between the BJB starter motor relay pin 1, circuit CE336 (GN/WH), harness side and PCM C175B-35, circuit CE336 (GN/WH), harness side. Is the resistance less than 5 ohms? Yes: INSTALL a new PCM. Refer to «ELECTRONIC ENGINE CONTROLS»(ref-372808) . TEST the system for normal operation. No: REPAIR circuit CE336 (GN/WH). TEST the system for normal operation.
A21 CHECK CIRCUIT CDC35 (BU/WH) FOR AN OPEN Ignition OFF. Connect: Starter Motor Relay. Disconnect: PCM C175B. Disconnect: Start Diode. Measure the resistance between the start diode cell, circuit CDC35 (BU/WH), harness side and PCM C1381B-16, circuit CDC35 (BU/WH), harness side. Is the resistance less than 5 ohms? Yes: GO to A22 . No: REPAIR circuit CDC35 (BU/WH) for an open. TEST the system for normal operation.
A22 CHECK THE CIRCUIT CE336 (GN/WH) BETWEEN THE BJB AND THE PCM Ignition OFF. Disconnect: PCM C175B. Measure the resistance between the BJB starter relay pin 1, circuit CE336 (GN/WH), harness side and PCM C1381B-37, circuit CE336 (GN/WH), harness side. Is the resistance less than 5 ohms? Yes: INSTALL a new PCM. Refer to «ELECTRONIC ENGINE CONTROLS»(ref-372808) . TEST the system for normal operation. No: REPAIR circuit CE336 (GN/WH). TEST the system for normal operation.
A23 CHECK STARTER MOTOR RELAY POWER NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector. Disconnect: Starter Motor Relay. Measure the voltage between BJB starter motor relay pin 5, circuit SBB10 (YE/RD), harness side and ground. Is the voltage greater than 10 volts? Yes: GO to A24 . No: VERIFY BJB fuse 10 (30A) is OK. If OK, REPAIR circuit SBB10 (YE/RD). TEST the system for normal operation. If not OK, REFER to the «SYSTEM WIRING DIAGRAMS»(ref-360982) to identify the possible causes of the circuit short.
A24 CHECK THE STARTER MOTOR RELAY Carry out the Starter Motor Relay Component Test. Refer to «COMPONENT TESTING»(ref-357210) for component testing. Did the starter motor relay pass the component test? Yes: For 3.5L vehicles, GO to A25 . For 3.5L GTDI vehicles, GO to A26 . No: INSTALL a new starter motor relay. TEST the system for normal operation.
A25 CHECK CIRCUIT CDC12 (YE) FOR AN OPEN Disconnect: PCM C175B. Measure the resistance between the BJB starter relay pin 2, circuit CDC12 (YE), harness side and PCM C175B-34, circuit CDC12 (YE), harness side. Is the resistance less than 5 ohms? Yes: INSTALL a new PCM. Refer to «ELECTRONIC ENGINE CONTROLS»(ref-372808) . No: REPAIR circuit CDC12 (YE). TEST the system for normal operation.
A26 CHECK CIRCUIT CDC12 (YE) FOR AN OPEN Ignition OFF. Disconnect: PCM C175B. Measure the resistance between the BJB starter relay pin 2, circuit CDC12 (YE), harness side and PCM C1381B-7, circuit CDC12 (YE), harness side. Is the resistance less than 5 ohms? Yes: INSTALL a new PCM. Refer to «ELECTRONIC ENGINE CONTROLS»(ref-372808) . No: REPAIR circuit CDC12 (YE). TEST the system for normal operation.

When the ignition switch is turned in the START position and released, the PCM receives a starter motor request signal through circuit CDC35 (BU/WH). With the vehicle in PARK or NEUTRAL, power flows from the PCM to the starter motor relay through circuit CE336 (GN/WH). A ground is supplied through circuit CDC12 (YE) from the PCM causing the starter motor relay coil to energize and the relay contacts close. This allows power from starter motor relay through circuit CDC25 (BN/GN) to the starter solenoid. The solenoid is grounded at the starter motor. Energizing the starter solenoid will engage the starter drive into the ring gear and closes the solenoid contacts, allowing power directly from the battery through circuit SDC02 (RD) to the starter motor to start the engine. The customer is no longer in the loop after the initial crank request, the customer may release the key to the RUN/START position. The PCM will disengage the starter motor based on engine running (rpm threshold), a set crank time has been exceeded or the ignition switch has been turned to the OFF position.