Starting System: Overview — Ford Fusion I facelift (2005-2012)

Normal Operation

Under normal operation, constant power is supplied to the starter relay on circuit SBB02 (YE/RD), the starter on circuit SDC02 (RD) and to the ignition switch on circuit SBB14 (BN/RD). When the key is placed in the START position, with the vehicle in PARK or NEUTRAL or with the clutch pedal depressed, power is supplied to the smart junction box (SJB) on circuit CDC36 (GN/WH) to the starter relay. Inputs from the transmission range (TR) sensor and clutch cutoff switch to the PCM provide a ground to the starter relay on circuit CDC12 (YE). When the coil of the relay is energized, it sends power to the starter motor on circuit CDC25 (BN/GN).

This pinpoint test is intended to diagnose the following

Battery
Fuse(s)
Ignition switch
Starter motor relay - non-serviceable (part of SJB)
PCM
Anti-theft system
Circuitry

Scheme 2

Scheme 2: PINPOINT TEST A: THE ENGINE DOES NOT CRANK

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Scheme 15

A1 CHECK THE BATTERY Check the battery condition and charge. Refer to «BATTERY, MOUNTING AND CABLES»(ref-291883) article. Is the battery OK? YES : Go to A2 . NO : CHARGE or INSTALL a new battery as necessary. REFER to «BATTERY, MOUNTING AND CABLES»(ref-291883) article. TEST the system for normal operation.
A2 CHECK THE PATS AND PCM FOR DTCs Check for PATS and PCM DTCs. Were any PATS and PCM DTCs retrieved? YES : REFER to «ANTI-THEFT - PASSIVE ANTI-THEFT SYSTEM (PATS)»(ref-291894) article to diagnose the PATS DTCs. REFER to «Introduction - Gasoline Engines»(ref-291242) article to diagnose the PCM DTCs. NO : For automatic transmission, go to A3 . For manual transmission, go to A4 .
A3 CHECK THE AUTOMATIC TRANSMISSION RANGE (TR) SENSOR Enter the following diagnostic mode on the scan tool: Transmission Control Module (TCM) DataLogger PID. While observing the TCM 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 RELAY ENABLE (STRT_RLY) PID Enter the following diagnostic mode on the diagnostic tool: PCM DataLogger/PID Monitor the PCM PID STRT_RLY with the ignition switch in the START position. Does the PID change from DISABLED to ENABLED? YES : Go to A5 . NO : Go to A12 .
A5 CHECK THE STARTER MOTOR CONTROL OUTPUT DETECTED (SMC_MON) PID Enter the following diagnostic mode on the diagnostic tool: PCM DataLogger/PID Monitor the PCM PID SMC_MON with the ignition switch in the START position. Does the PID change from OFF to ON? YES : Go to A6 . NO : Go to A19 .
A6 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 A7 . NO : INSTALL a new battery ground cable. REFER to «BATTERY, MOUNTING AND CABLES»(ref-291883) article. TEST the system for normal operation.
A7 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 A8 . NO : CLEAN the starter motor mounting flange and make sure the starter motor is correctly mounted. TEST the system for normal operation.
A8 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 A9 . NO : INSTALL a new positive battery cable. REFER to «BATTERY, MOUNTING AND CABLES»(ref-291883) article. TEST the system for normal operation.
A9 CHECK THE STARTER MOTOR B-PIN Connect one end of a fused (30A) jumper wire to starter motor solenoid C197A, 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 A10 . NO : INSTALL a new starter motor. REFER to «Starter Motor - 2.3L»(ref-291901-S09314276032008073000000) , «Starter Motor - 3.0L»(ref-291901-S16052701762008073000000) or «Starter Motor - 3.5L»(ref-291901-S42180690122008073000000) . TEST the system for normal operation.
A10 CHECK THE CIRCUIT TO THE STARTER MOTOR CAUTION: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector. Key in OFF position. Disconnect: Starter Motor Solenoid C197B Disconnect: SJB C2280A Measure the resistance between starter solenoid S-terminal C197B, circuit CDC25 (BN/GN) harness side and the SJB C2280A-17, circuit CDC25 (BN/GN) harness side. Is the resistance less than 5 ohms? YES : Go to A11 . NO : REPAIR the circuit CDC25 (BN/GN). TEST the system for normal operation.
A11 CHECK THE STARTER MOTOR RELAY POWER Connect: Starter Motor Solenoid C197B Connect: SJB C2280A Disconnect: SJB C2280F Measure the voltage between SJB C2280F-1, circuit SBB02 (YE/RD) and ground. Is the voltage greater than 10 volts? YES : INSTALL a new SJB. TEST the system for normal operation. NO : REPAIR circuit SBB02 (YE/RD). TEST the system for normal operation.
A12 CHECK THE STARTER DIODE Disconnect: Starter Diode Carry out a Starter Diode Test. Is the starter diode open or shorted? YES : INSTALL a new starter diode. TEST the system for normal operation. NO : Go to A13 .
A13 CHECK CIRCUIT CDC35 (BU/WH) FOR VOLTAGE Measure the voltage between battery junction box (BJB) starter diode cell, circuit CDC35 (BU/WH) and ground with the ignition switch in the START position. Is the voltage greater than 10 volts? YES : Go to A16 . NO : Go to A14 .
A14 CHECK CIRCUIT SBB14 (BN/RD) FOR VOLTAGE Disconnect: Ignition Switch C250 Measure the voltage between ignition switch C250-4, circuit SBB14 (BN/RD), harness side and ground. Is the voltage greater than 10 volts? YES : Go to A15 . NO : REPAIR circuit SBB14 (BN/RD). TEST the system for normal operation.
A15 CHECK THE IGNITION SWITCH Carry out the Ignition Switch Component Test. Refer to COMPONENT TESTING. Did the ignition switch pass the component test? YES : REPAIR circuit CDC35 (BU/WH). TEST the system for normal operation. NO : INSTALL a new ignition switch. REFER to «STEERING COLUMN SWITCHES»(ref-291886) article. TEST the system for normal operation.
A16 CHECK CIRCUIT CDC36 (GN/WH) FOR AN OPEN Disconnect: Start Diode Disconnect: PCM C175B Measure the resistance between the BJB start diode cell, circuit CDC36 (BU/WH), harness side and PCM C175B-19, circuit CDC36 (BU/WH), harness side. Is the resistance less than 5 ohms? YES : Go to A17 . NO : REPAIR circuit CDC36 (BU/WH). TEST the system for normal operation.
A17 CHECK THE START SIGNAL TO THE STARTER MOTOR RELAY Connect: Start Diode Disconnect: SJB C2280B Measure the resistance between the SJB C2280B-30, circuit CDC36 (GN/WH), harness side and C175B-19, circuit CDC36 (GN/WH), harness side. Is the resistance less than 5 ohms? YES : Go to A18 . NO : REPAIR circuit CDC36 (BU/WH). TEST the system for normal operation.
A18 CHECK CIRCUIT CDC35 (BU/WH) FOR AN OPEN Connect: SJB C2280B Measure the resistance between PCM C175B-19, circuit CDC36 (GN/WH), harness side and PCM C175B-10, circuit CDC35 (BU/WH) harness side. Is the resistance less than 5 ohms? YES : INSTALL a new PCM. REFER to «ELECTRONIC ENGINE CONTROLS - 2.3L»(ref-291907) article, «ELECTRONIC ENGINE CONTROLS - 3.0L (4V)»(ref-291913) article or «ELECTRONIC ENGINE CONTROLS - 3.5L»(ref-291920) article. TEST the system for normal operation. NO : REPAIR circuit CDC35 (BU/WH). TEST the system for normal operation.
A19 CHECK CIRCUIT CDC12 (YE) FOR AN OPEN Key in OFF position. Disconnect: PCM C175B Disconnect: SJB C2280A Measure the resistance between SJB C2280A-18, circuit CDC12 (YE), harness side and PCM C175B-34, circuit CDC12 (YE), harness side. Is the resistance less than 5 ohms? YES : Go to A20 . NO : REPAIR circuit CDC12 (YE). TEST the system for normal operation.
A20 CHECK STARTER MOTOR RELAY Key in OFF position. Disconnect: SJB C2280B Disconnect: SJB C2280A Measure the resistance between SJB C2280A-18, circuit CDC12 (YE), component side and SJB C2280B-30, circuit CE336 (GN/WH), component side. Is the resistance less than 5 ohms? YES : INSTALL a new PCM. REFER to «ELECTRONIC ENGINE CONTROLS - 2.3L»(ref-291907) article, «ELECTRONIC ENGINE CONTROLS - 3.0L (4V)»(ref-291913) article or «ELECTRONIC ENGINE CONTROLS - 3.5L»(ref-291920) article. TEST the system for normal operation. NO : INSTALL a new SJB. 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 (SMR) 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 CDC36 (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.