Starting System: Overview — Lincoln MKZ I рестайлинг (2009-2012)

Normal Operation

Under normal operation, constant power is supplied to the starter relay on circuit SBB05 (GY/RD), the starter on circuit SBB02 (RD) and to the ignition switch on circuit SBP27 (BU/RD). When the key is placed in the START position, with the vehicle in PARK or NEUTRAL or with the clutch pedal depressed, power flows to the starter motor relay through CE336 (GN/WH). 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
PCM
TR sensor
Clutch cutoff switch
Circuitry
Start diode
Anti-theft system

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 charge. Refer to «PINPOINT TEST A: BATTERY CONDITION TEST»(ref-355968-S31115854422010013000000) . Is the battery OK? Yes: GO to A2 . No: CHARGE or INSTALL a new battery as necessary. REFER to «REMOVAL AND INSTALLATION»(ref-355968-S21457165732010013000000) . TEST the system for normal operation.
A2 CHECK THE PCM FOR DTCs 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-356000) . All other PCM DTCs, REFER to «INTRODUCTION - GASOLINE MODELS»(ref-355661) or «INTRODUCTION - HYBRID»(ref-355647) . No: For automatic transmission, go to A3 . For manual transmission, go to A4 .
A3 CHECK THE AUTOMATIC TR SENSOR Enter the following diagnostic mode on the scan tool: TCM DataLogger PID. While observing the Transmission Control Module (TCM) TR sensor PID, place the vehicle in PARK and NEUTRAL. Does the PID match the gear selection? Yes: GO to A5 . No: GO to the appropriate Automatic Transmission article to diagnose the TR sensor.
A4 CHECK THE CLUTCH CUTOFF SWITCH (CPP_BOT) PID Enter the following diagnostic mode on the scan tool: DataLogger - PCM. While observing the CPP_ BOT PID, fully disengage the clutch. Does the PID change from NO to YES? Yes: GO to A5 . No: GO to A28 .
A5 CHECK THE STARTER MOTOR CONTROL OUTPUT DETECTED (SMC_MON) PID Enter the following diagnostic mode on the scan tool: DataLogger - PCM. Monitor the PCM PID SMC_MON with the ignition switch in the START position. NOTE: For manual transaxle, fully disengage the clutch. Does the PID change from OFF to ON? Yes: GO to A6 . No: GO to A13 .
A6 CHECK THE STARTER MOTOR RELAY ENABLE (STRT_RLY) PID Enter the following diagnostic mode on the scan tool: DataLogger - PCM. Monitor the PCM PID STRT_RLY with the ignition switch in the START position. NOTE: For manual transaxle, fully disengage the clutch. Does the PID change from DISABLED to ENABLED? Yes: GO to A7 . No: GO to A24 .
A7 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 Battery Junction Box (BJB) starter motor relay pin 30, circuit SBB05 (GY/RD), harness side and ground. Is the voltage greater than 10 volts? Yes: GO to A8 . No: VERIFY BJB fuse 5 (30A) is OK. If OK, REPAIR circuit SBB05 (GY/RD). TEST the system for normal operation. If not OK, REFER to the appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short.
A8 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 A9 . No: INSTALL a new battery ground cable. REFER to «REMOVAL AND INSTALLATION»(ref-355968-S25250684482010013000000) (2.5L), «REMOVAL AND INSTALLATION»(ref-355968-S29807266762010013000000) (3.0L) and/or «REMOVAL AND INSTALLATION»(ref-355968-S23806754962010013000000) (3.5L) . TEST the system for normal operation.
A9 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 A10 . No: CLEAN the starter motor mounting flange and make sure the starter motor is correctly mounted. TEST the system for normal operation.
A10 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 A11 . No: INSTALL a new positive battery cable. REFER to «REMOVAL AND INSTALLATION»(ref-355968-S25250684482010013000000) (2.5L), «REMOVAL AND INSTALLATION»(ref-355968-S29807266762010013000000) (3.0L) and/or «REMOVAL AND INSTALLATION»(ref-355968-S23806754962010013000000) (3.5L) . TEST the system for normal operation.
A11 CHECK THE STARTER MOTOR B-PIN Connect one end of a fused (30A) 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 A12 . No: INSTALL a new starter motor. REFER to «Removal and Installation»(ref-355983-S38471229502010013000000) (2.5L), «Removal and Installation»(ref-355983-S03348766152010050500000) (3.0L) or «Removal and Installation»(ref-355983-S37238001662010050500000) (3.5L). TEST the system for normal operation.
A12 CHECK THE CIRCUIT TO THE STARTER MOTOR 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. 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 87, 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.
A13 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 30, circuit SBB05 (GY/RD), harness side and ground. Is the voltage greater than 10 volts? Yes: GO to A14 . No: VERIFY BJB fuse 5 (30A) is OK. If OK, REPAIR circuit SBB05 (GY/RD). TEST the system for normal operation. If not OK, REFER to the appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short.
A14 CHECK THE STARTER MOTOR RELAY Carry out the Starter Motor Relay Component Test. Refer to «COMPONENT TESTING»(ref-357066) for component testing. Did the starter motor relay pass the component test? Yes: Go to A15 . No: INSTALL a new starter motor relay. TEST the system for normal operation.
A15 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 A16 . No: INSTALL a new start diode. TEST the system for normal operation.
A16 CHECK THE START SIGNAL TO THE STARTER MOTOR RELAY Connect: Start Diode. Measure the voltage between the BJB starter motor relay pin 86, circuit CE336 (GN/WH), harness side and ground with the ignition switch in the START position. NOTE: For manual transaxle, fully disengage the clutch. Is the voltage greater than 10 volts? Yes: For 2.5L and 3.0L vehicles, go to A20 . For 3.5L vehicles, go to A22 . No: Go to A17 .
A17 CHECK CIRCUIT CE336 (GN/WH) FOR AN OPEN BETWEEN START DIODE AND STARTER RELAY Disconnect: Start Diode. Measure the resistance between the start diode, circuit CE336 (GN/WH), harness side and BJB starter motor relay pin 86, circuit CE336 (GN/WH), harness side. Is the resistance less than 5 ohms? Yes: GO to A18 . No: REPAIR circuit CE336 (GN/WH) for an open. TEST the system for normal operation.
A18 CHECK CIRCUIT SBP27 (BU/RD) FOR VOLTAGE Connect: Starter Motor Relay. Connect: Start Diode. 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 A19 . No: VERIFY SJB fuse 27 (20 A) is OK. If OK, REPAIR circuit SBP27 (BU/RD) for an open. TEST the system for normal operation. If not OK, REFER to the appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short.
A19 CHECK THE IGNITION SWITCH Carry out the Ignition Switch Component Test. Refer to «COMPONENT TESTING»(ref-357066) 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 «REMOVAL AND INSTALLATION»(ref-355950-S19274158712010013000000) . TEST the system for normal operation.
A20 CHECK CIRCUIT CDC35 (BU/WH) FOR AN OPEN 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-16, circuit CDC35 (BU/WH), harness side. Is the resistance less than 5 ohms? Yes: Go to A21 . No: REPAIR circuit CDC35 (BU/WH) for an open. TEST the system for normal operation.
A21 CHECK THE CIRCUIT CE336 (GN/WH) BETWEEN THE BJB AND THE PCM Connect: Start Diode. Ignition OFF. Measure the resistance between the BJB starter motor relay pin 86, circuit CE336 (GN/WH), harness side and PCM C175B-37, circuit CE336 (GN/WH), harness side. Is the resistance less than 5 ohms? Yes: INSTALL a new PCM. REFER to «INSTALLATION»(ref-355966-S35854030482010013000000) (2.5L), , «INSTALLATION»(ref-355967-S06718515432010013000000) (3.0L) or «INSTALLATION»(ref-355978-S23851793532010013000000) (3.5L) . TEST the system for normal operation. No: REPAIR circuit CE336 (GN/WH). TEST the system for normal operation.
A22 CHECK CIRCUIT CDC35 (BU/WH) FOR AN OPEN 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-10, circuit CDC35 (BU/WH), harness side. Is the resistance less than 5 ohms? Yes: GO to A23 . No: REPAIR circuit CDC35 (BU/WH) for an open. TEST the system for normal operation.
A23 CHECK CIRCUIT CE336 (GN/WH) BETWEEN THE BJB AND THE PCM Ignition OFF. Connect: Start Diode. Measure the resistance between the BJB starter motor relay pin 86, circuit CE336 (GN/WH), harness side and PCM C175B-19, circuit CE336 (GN/WH), harness side. Is the resistance less than 5 ohms? Yes: INSTALL a new PCM. REFER to «INSTALLATION»(ref-355966-S35854030482010013000000) (2.5L), , «INSTALLATION»(ref-355967-S06718515432010013000000) (3.0L) or «INSTALLATION»(ref-355978-S23851793532010013000000) (3.5L) . TEST the system for normal operation. No: REPAIR circuit CE336 (GN/WH). TEST the system for normal operation.
A24 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 30, circuit SBB05 (GY/RD), harness side and ground. Is the voltage greater than 10 volts? Yes: GO to A25 . No: VERIFY BJB fuse 5 (30A) is OK. If OK, REPAIR circuit SBB05 (GY/RD). TEST the system for normal operation. If not OK, REFER to the appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short.
A25 CHECK THE STARTER MOTOR RELAY Carry out the Starter Motor Relay Component Test. Refer to «COMPONENT TESTING»(ref-357066) for component testing. Did the starter motor relay pass the component test? Yes: For 2.5L and 3.0L vehicles, go to A26 . For 3.5L vehicles, go to A27 . No: INSTALL a new starter motor relay. TEST the system for normal operation.
A26 CHECK CIRCUIT CDC12 (YE) FOR AN OPEN Disconnect: PCM C175B. Measure the resistance between the BJB starter relay pin 85, 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 «INSTALLATION»(ref-355966-S35854030482010013000000) (2.5L), , «INSTALLATION»(ref-355967-S06718515432010013000000) (3.0L) or «INSTALLATION»(ref-355978-S23851793532010013000000) (3.5L) . TEST the system for normal operation. No: REPAIR circuit CDC12 (YE). TEST the system for normal operation.
A27 CHECK CIRCUIT CDC12 (YE) FOR AN OPEN Disconnect: PCM C175B. Measure the resistance between the BJB starter relay pin 85, 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 «INSTALLATION»(ref-355966-S35854030482010013000000) (2.5L), , «INSTALLATION»(ref-355967-S06718515432010013000000) (3.0L) or «INSTALLATION»(ref-355978-S23851793532010013000000) (3.5L) . TEST the system for normal operation. No: REPAIR circuit CDC12 (YE). TEST the system for normal operation.
A28 CHECK CIRCUIT GD120 (BK/GN) FOR AN OPEN Ignition OFF. Disconnect: Clutch Cutoff Switch C2072. Measure the resistance between clutch cutoff switch C2072-2, circuit GD120 (BK/GN), harness side and ground. Is the resistance less than 5 ohms? Yes: Go to A29 . No: REPAIR circuit GD120 (BK/GN). TEST the system for normal operation.
A29 CHECK CIRCUIT CE903 (BU/OG) FOR AN OPEN Ignition OFF. Disconnect: PCM C175T. Measure the resistance between clutch cutoff switch C2072-1, 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 A30 . No: REPAIR circuit CE903 (BU/OG). TEST the system for normal operation.
A30 CHECK CPP SWITCH FOR AN OPEN Measure the resistance between 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 «INSTALLATION»(ref-355966-S35854030482010013000000) (2.5L) , «INSTALLATION»(ref-355967-S06718515432010013000000) (3.0L) or «INSTALLATION»(ref-355978-S23851793532010013000000) (3.5L) . TEST the system for normal operation. No: REPLACE the clutch cutoff switch. TEST the system for normal operation.

When the ignition switch is turned to 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 or with the clutch pedal depressed, 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.