Starting System: Overview — Ford Focus II facelift (2007-2011)

Principles of Operation

On vehicles equipped with automatic transaxles, when the ignition switch is turned to the START position and the vehicle is in the NEUTRAL or PARK position, the starter relay switches power to the starter solenoid, causing the starter motor to engage.

Vehicles equipped with manual transaxles have a clutch cutoff switch in the starter control circuit. When the clutch pedal is applied and the ignition switched is turned to the START position, the starter relay switches power to the starter solenoid causing the starter motor to engage.

The starting system is electronically controlled by the passive anti-theft system (PATS). The PATS recognizes the correct electronically coded ignition key and signals the PCM to provide a ground for the starter relay. The energized relay provides voltage to the starter solenoid, thereby allowing the starter motor to activate.

Normal Operation

Under normal operation, the battery junction box (BJB) supplies constant power to the starter motor relay on circuit SBB11 (BU/RD) through fuse 11 (30A). On vehicles with automatic transaxles, when the key is placed in the START position with the vehicle in PARK or NEUTRAL, the transmission range (TR) sensor provides power on circuit VET28 (GY/VT) and the PCM provides ground on circuit CDC12 (YE). On vehicles with manual transaxles, when the key is placed in the START position with the clutch pedal depressed, the clutch cutoff switch sends a signal to the PCM on circuit CE903 (BU/OG) and provides ground to the starter motor relay. The coil of the relay is energized and sends power to the starter motor on circuit CDC25 (BN/GN). The solenoid is grounded at the starter motor. Energizing the starter solenoid will engage the starter drive into the flywheel/flexplate 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
Starter motor
Starter motor relay
Start diode
Circuit
PCM

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Scheme 3: PINPOINT TEST A: THE ENGINE DOES NOT CRANK

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A1 CHECK THE BATTERY Check the battery condition and charge. Refer to «BATTERY, MOUNTING AND CABLES»(ref-357167) . Is the battery OK? YES : Go to A2 . NO : CHARGE or INSTALL a new battery as necessary. REFER to «BATTERY, MOUNTING AND CABLES»(ref-357167) . 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-357188) to diagnose the PATS DTCs. REFER to appropriate INTRODUCTION- GASOLINE MODELS 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 PID Enter the following diagnostic mode on the diagnostic tool: PCM DataLogger/PID While observing the PCM TR sensor PID, place the vehicle in PARK and NEUTRAL. Does the PID match the gear selection? YES : Go to A5 . NO : Go to «AUTOMATIC TRANSAXLE/TRANSMISSION - 4F27E»(ref-357160) to diagnose the TR sensor.
A4 CHECK THE START INHIBIT CLUTCH CUTOFF SWITCH (CPP_BT) PID Enter the following diagnostic mode on the diagnostic tool: PCM DataLogger/PID While observing the CPP_BT PID, fully disengage the clutch. Does the PID change from NO to YES? YES : Go to A5 . NO : Go to A22 .
A5 CHECK THE STARTER MOTOR RELAY ENABLE (STRT_RLY) PID Enter the following diagnostic mode on the diagnostic tool: PCM DataLogger/PID NOTE: For manual transaxle, fully disengage the clutch. 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 A6 . NO : Go to A12 .
A6 CHECK THE STARTER MOTOR CONTROL OUTPUT DETECTED (SMC_MON) PID Enter the following diagnostic mode on the diagnostic tool: PCM DataLogger/PID NOTE: For manual transaxle, fully disengage the clutch. 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 A7 . NO : Go to A20 .
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-357167) . 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 C197-1, 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-357167) . TEST the system for normal operation.
A10 CHECK THE STARTER MOTOR B-PIN Connect one end of a fused (30A) jumper wire to starter motor solenoid C197-1, circuit SDC02 (RD). Momentarily connect the other end of the jumper to starter motor C197-2, 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-357162-S13925550662010030800000) . TEST the system for normal operation.
A11 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 C197 Disconnect: Starter Motor Relay Measure the resistance between starter motor C197-2, circuit CDC25 (BN/GN) and battery junction box (BJB) starter relay pin 5, circuit CDC25 (BN/GN). Is the resistance less than 5 ohms? YES : INSTALL a new starter motor relay. TEST the system for normal operation. NO : REPAIR the circuit CDC25 (BN/GN). TEST the system for normal operation.
A12 CHECK THE STARTER MOTOR RELAY Carry out the Starter Motor Relay Component Test. Refer to appropriate COMPONENT TESTING article. Did the starter motor relay pass the component test? YES : Go to A13 . NO : INSTALL a new starter motor relay. TEST the system for normal operation.
A13 CHECK THE START DIODE Disconnect: Start Diode Carry out a Start Diode Test. Is the start diode open or shorted? YES : INSTALL a new start diode. TEST the system for normal operation. NO : Go to A14 .
A14 CHECK CIRCUIT VET28 (GY/VT) FOR VOLTAGE NOTE: For manual transaxle, fully disengage the clutch. Measure the voltage between BJB starter motor relay pin 2, circuit VET28 (GY/VT) and ground with the ignition switch in the START position. Is the voltage greater than 10 volts? YES : Go to A17 . NO : Go to A15 .
A15 CHECK CIRCUIT SBP27 (BU/RD) FOR VOLTAGE 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 A16 . NO : REPAIR circuit SBP27 (BU/RD). TEST the system for normal operation.
A16 CHECK THE IGNITION SWITCH Carry out the Ignition Switch Component Test. Refer to appropriate COMPONENT TESTING article. 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-357145) . TEST the system for normal operation.
A17 CHECK CIRCUIT CE619 (BU/BN) FOR AN OPEN Disconnect: Start Diode Disconnect: PCM C175B Measure the resistance between the BJB start diode cell, circuit CE619 (BU/BN), harness side and PCM C175B-37, circuit CE619 (BU/BN), harness side. Is the resistance less than 5 ohms? YES : Go to A18 . NO : REPAIR circuit CE619 (BU/BN). TEST the system for normal operation.
A18 CHECK THE START SIGNAL TO THE STARTER MOTOR RELAY Connect: Start Diode Disconnect: Starter Motor Relay Measure the resistance between the starter motor relay pin 2, circuit VET28 (GY/VT), harness side and C175B-37, circuit CE619 (BU/BN), harness side. Is the resistance less than 5 ohms? YES : Go to A19 . NO : REPAIR circuit CE619 (BU/BN) or VET28 (GY/VT). TEST the system for normal operation.
A19 CHECK CIRCUIT CDC35 (BU/WH) FOR AN OPEN Connect: Starter Motor Relay Measure the resistance between PCM C175B-37, circuit CE619 (BU/BN), harness side and PCMC175B-16, circuit CDC35 (BU/WH) harness side. Is the resistance less than 5 ohms? YES : INSTALL a new PCM. REFER to «ELECTRONIC ENGINE CONTROLS»(ref-357164) . TEST the system for normal operation. NO : REPAIR circuit CDC35 (BU/WH) or CE619 (BU/BN). TEST the system for normal operation.
A20 CHECK THE STARTER MOTOR RELAY Carry out the Starter Motor Relay Component Test. Refer to appropriate COMPONENT TESTING article. Did the starter motor relay pass the component test? YES : Go to A21 . NO : INSTALL a new starter motor relay. TEST the system for normal operation.
A21 CHECK CIRCUIT CDC12 (YE) FOR AN OPEN Key in OFF position. Disconnect: PCM C175B Disconnect: Starter Motor Relay Measure the resistance between the starter motor relay pin 1, circuit CDC12 (YE), harness side and PCM C175B-7, circuit CDC12 (YE), harness side. Is the resistance less than 5 ohms? YES : INSTALL a new PCM. REFER to «ELECTRONIC ENGINE CONTROLS»(ref-357164) . TEST the system for normal operation. NO : REPAIR circuit CDC12 (YE). TEST the system for normal operation.
A22 CHECK CIRCUIT GD134 (BK/VT) FOR AN OPEN Key in OFF position. Disconnect: Clutch Cutoff Switch C2072 Measure the resistance between the clutch cutoff switch C2072-1, circuit GD134 (BK/VT), harness side and ground. Is the resistance less than 5 ohms? YES : Go to A23 . NO : REPAIR circuit GD134 (BK/VT). TEST the system for normal operation.
A23 CHECK CIRCUIT CE903 (BU/OG) FOR AN OPEN Key in OFF position. Disconnect: PCM C175T Measure the resistance between the clutch cutoff switch C2072-2, circuit CE903 (BU/OG), harness side and PCM C175T-26, circuit CE903 (BU/OG), harness side. Is the resistance less than 5 ohms? YES : Go to A24 . NO : REPAIR circuit CE903 (BU/OG). TEST the system for normal operation.
A24 CHECK CLUTCH CUTOFF SWITCH FOR AN OPEN Measure the resistance between the clutch cutoff switch C2072-2 and C2072-1, component side, fully disengage the clutch. Is the resistance less than 5 ohms? YES : INSTALL a new PCM. REFER to «ELECTRONIC ENGINE CONTROLS»(ref-357164) . TEST the system for normal operation. NO : REPLACE the clutch cutoff switch. 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 or clutch pedal is depressed, power flows from the PCM to the starter motor relay through circuits CE619 (BU/BN) and VET28 (GY/VT). 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.