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Starting System: Overview Mercury Milan I

Starter 12 illustrations ~1088 words

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 CDC35 (BU/WH) through the SJB fuse 10 (30A) to the starter relay. Inputs from the transmission range (TR) sensor and clutch cutoff switch to the powertrain control module (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).

Possible Causes

  1. Battery
  2. Fuse(s)
  3. Ignition switch
  4. Starter relay (part of SJB)
  5. Powertrain control module (PCM)
  6. Anti-theft system
  7. Circuitry

Scheme 2

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

Scheme 3

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Scheme 13
  1. A1 CHECK THE BATTERY Check the battery condition and charge. Refer to «BATTERY, MOUNTING AND CABLES»(ref-271102) . Is the battery OK? YES : Go to A2 . NO : CHARGE or INSTALL a new battery as necessary. REFER to «BATTERY, MOUNTING AND CABLES»(ref-271102) . TEST the system for normal operation.
  2. A2 CHECK THE CONDITION OF THE PATS NOTE: The PATS diagnostic trouble codes (DTCs) are the only DTCs of concern in this step. Only repair retrieved non-PATS DTCs if a customer concern is reported. Check for PATS DTCs. Were any PATS DTCs retrieved? YES : REFER to «ANTI-THEFT - PATS»(ref-271118) to diagnose the PATS DTCs. NO : Go to A3 .
  3. A3 CHECK THE AUTOMATIC TRANSMISSION RANGE (TR) SENSOR Enter the following diagnostic mode on the scan tool: PCM TR sensor 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 A4 . NO : Go to the appropriate «AUTOMATIC TRANSAXLE/TRANSMISSION - FNR5»(ref-271121) or «AUTOMATIC TRANSAXLE/TRANSMISSION - 6 SPEED»(ref-271076) to diagnose the TR sensor.
  4. A4 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 A5 . NO : INSTALL a new battery ground cable. REFER to «BATTERY, MOUNTING AND CABLES»(ref-271102) . TEST the system for normal operation.
  5. A5 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 A6 . NO : CLEAN the starter motor mounting flange and make sure the starter motor is correctly mounted. TEST the system for normal operation.
  6. A6 CHECK THE POWER SUPPLY TO THE STARTER MOTOR Measure the voltage between the starter motor B-pin and ground. Is the voltage greater than 10 volts? YES : Go to A7 . NO : INSTALL a new positive battery cable. REFER to «BATTERY, MOUNTING AND CABLES»(ref-271102) . TEST the system for normal operation.
  7. A7 CHECK THE STARTER MOTOR B-PIN Connect one end of a fused (30A) jumper wire to the B-terminal of the starter motor. Momentarily connect the other end of the jumper to the starter motor S-terminal. Did the starter motor engage and the engine crank? YES : Go to A8 . NO : INSTALL a new starter motor. REFER to «Starter Motor - 2.3L»(ref-271064-S40919744132007110800000) or «Starter Motor - 3.0L»(ref-271064-S00077468832007110800000) or «Starter Motor - 3.5L»(ref-271064-S42602820552007110800000) . TEST the system for normal operation.
  8. A8 CHECK THE STARTER MOTOR RELAY POWER Measure the voltage between smart junction box (SJB) C2280f-1, circuit SBB02 (YE/RD) and ground. Is the voltage greater than 10 volts? YES : Go to A9 . NO : REPAIR the circuit. TEST the system for normal operation.
  9. A9 CHECK THE START SIGNAL TO THE STARTER MOTOR RELAY Disconnect: SJB C2280b NOTE: For manual transaxle, fully disengage the clutch. Measure the voltage between SJB C2280b-30, circuit CDC35 (BU/WH), harness side and ground with the ignition switch in the START position. Is the voltage greater than 10 volts? YES : Go to A12 . NO : Go to A10 .
  10. A10 CHECK CIRCUIT CDC35 (BU/WH) FOR AN OPEN Key in OFF position. Disconnect: Ignition Switch C250 Measure the resistance between SJB C2280b-30, circuit CDC35 (BU/WH), harness side and ignition switch C250-7, circuit CDC35 (BU/WH). Is the resistance less than 5 ohms? YES : Go to A11 . NO : REPAIR the circuit. TEST the system for normal operation.
  11. A11 CHECK CIRCUIT SBB14 (BN/RD) Measure the voltage between ignition switch C250-4, circuit SBB14 (BN/RD) and ground. Is the voltage greater than 10 volts? YES : INSTALL a new ignition switch. TEST the system for normal operation. NO : REPAIR the circuit. TEST the system for normal operation.
  12. A12 CHECK THE GROUND SIGNAL TO THE STARTER RELAY Disconnect: SJB C2280a NOTE: For manual transaxle, fully disengage the clutch. Measure the voltage between SJB C2280b-30, circuit CDC35 (BU/WH) and SJB C2280a-18, circuit CDC12 (YE), while placing the ignition switch in the START position. Is the voltage greater than 10 volts? YES : Go to A15 . NO : Go to A13 .
  13. A13 CHECK CIRCUIT CDC12 (YE) FOR AN OPEN Key in OFF position. Disconnect: PCM C175B 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 : For 2.3L vehicles, INSTALL a new PCM. For 3.0L and 3.5L vehicles, go to A14 . NO : REPAIR the circuit. TEST the system for normal operation.
  14. A14 CHECK CIRCUIT CBP13 (GY/BN) FOR POWER TO THE PCM Measure the voltage between PCM C175b-10, circuit CBP13 (GY/BN) and ground, while placing the ignition switch in the START position. Is the voltage greater than 10 volts? YES : INSTALL a new PCM. REFER to «ELECTRONIC ENGINE CONTROLS - 2.3L»(ref-271070) , «ELECTRONIC ENGINE CONTROLS - 3.0L (4V)»(ref-271071) or «ELECTRONIC ENGINE CONTROLS - 3.5L»(ref-271135) . TEST the system for normal operation. NO : REPAIR the circuit. TEST the system for normal operation.
  15. A15 CHECK THE CIRCUIT TO THE STARTER MOTOR Key in OFF position. Disconnect: Starter Solenoid C197b 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 : INSTALL a new SJB. TEST the system for normal operation. NO : REPAIR the circuit. TEST the system for normal operation.

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