Starting System Operation
NORMAL OPERATION: THE INITIAL ENGINE CRANKING EVENT OCCURS WHEN THE KIN BUTTON IS PRESSED AND THE ENGINE CRANK REQUEST IS SENT TO THE RF HUB.
- THE RFH RECEIVES THE REQUEST FROM THE KIN AND THEN LOOKS FOR THE VALID KEY FOB BY USING THE LF ANTENNAS.
- IF THE RFH DETECTS A VALID KEY FOB AND THE BRAKE IS ENGAGED, THE RFH SENDS A START/CRANK MESSAGE ON THE CONTROLLER AREA NETWORK (CAN).
- IF THE PCM DETERMINES THAT A CRANK EVENT IS ALLOWED, A CRANK HOLD SIGNAL IS SENT TO THE BCM.
- THE BCM COMPLETES THE RELAY COIL CIRCUIT AND ENERGIZES STARTER RELAY 2.
- THE PCM COMPLETES THE RELAY COIL CIRCUIT AND ENERGIZES STARTER RELAY 1, ENGAGING THE STARTER MOTOR.
- AFTER THE ENGINE STARTS (ENGINE SPEED ABOVE A CALIBRATED THRESHOLD), THE PCM TURNS OFF STARTER RELAY 1 AND THE STARTER IS DISENGAGED. THE STARTER IS DISENGAGED IF THE ENGINE DOES NOT START AFTER 10 SECONDS. THE IGNITION STATE IS CHANGED TO RUN.
- TRANSPONDER BACKUP MODE STARTING: THERE IS A LF COIL LOCATED IN THE KIN THAT CAN COMMUNICATE WITH THE KEY FOBS TRANSPONDER IN CLOSE RANGE IF THE FOB BATTERY IS DEAD AND COMPLETE THE AUTHENTICATION. IN THE EVENT OF A KEY FOB ISSUE (1), PUSH THE FRONT EDGE OF THE KEY FOB AGAINST THE START BUTTON AND HOLD IT THERE FOR A FEW SECONDS TO START THE VEHICLE.
- EMERGENCY SHUTOFF: THE ENGINE CAN BE MANUALLY SHUT DOWN BY THE DRIVER WITH SPEEDS OVER 5 MPH (8 KM/H) IN ANY GEAR.
ENGINE STOP/START (ESS) EVENT: IN ORDER TO KEEP THE VEHICLE ELECTRICAL SYSTEMS OPERATING WITHOUT INTERRUPTION DURING AN ESS ENGINE CRANKING EVENT THE MAIN AND AUXILIARY BATTERIES ARE DISCONNECTED DURING THE INITIAL STARTER ENGAGEMENT. THIS IS ACCOMPLISHED BY ENERGIZING THE POWER CONTROL RELAY TO BREAK THE CONNECTION.
DUAL BATTERY ESS STARTING SYSTEMS: THE GENERIC GRAPHIC BELOW IS DEPICTING A SYSTEM WITH A SMART ALTERNATOR. HOWEVER, THE ESS STARTING SYSTEM OPERATES THE SAME ON VEHICLES EQUIPPED WITH A STANDARD ALTERNATOR AND CHARGING SYSTEM. THE GRAPHIC BELOW SHOWS THE POWER CONTROL RELAY DE-ENERGIZED (BATTERIES CONNECTED AND CHARGING).
THE ENGINE STOP/START (ESS) SYSTEM STOPS AND STARTS THE ENGINE WHEN THE VEHICLE IS AT A STOP AND CERTAIN CONDITIONS ARE MET TO LOWER CARBON DIOXIDE (CO2) EMISSIONS. THE POWERTRAIN CONTROL MODULE (PCM) IS THE MAIN MODULE CONTROLLING OPERATION OF THE ESS STARTING SYSTEM. THE SYSTEM DEFAULTS TO ACTIVE ON EACH IGNITION CYCLE. THERE IS A CUSTOMER SELECTABLE STOP/START OFF SWITCH THAT WILL DISABLE THE SYSTEM. THE SWITCH IS A SMART DEVICE THAT SENDS SIGNALS OVER A LIN BUS CIRCUIT TO THE BODY CONTROL MODULE. THE POWERTRAIN CONTROL MODULE (PCM) RECEIVES THE SWITCH SIGNAL MESSAGE OVER THE CAN BUS.
THE GENERIC GRAPHIC BELOW SHOWS MOST OF THE SYSTEM COMPONENTS AND THE RELATION BETWEEN THE BATTERY, STARTING AND CHARGING SYSTEMS. THERE ARE FOUR PRIMARY COMPONENTS THAT CONNECT THE STARTING, CHARGING AND VEHICLE ELECTRICAL SYSTEMS ON THE DUAL BATTERY SYSTEM. THESE ARE THE MAIN BATTERY, AUXILIARY BATTERY, POWER CONTROL RELAY AND DUAL BATTERY SYSTEM FUSE. THE POWER CONTROL RELAY SEPARATES THE SYSTEM INTO TWO SIDES, THE MAIN BATTERY SIDE AND AUXILIARY BATTERY SIDE. THE GRAPHIC SHOWS A SIMPLIFIED DIAGRAM OF THE COMPONENTS FOR EASE IN UNDERSTANDING THE SYSTEM CONFIGURATION.
THE BATTERY, STARTING AND CHARGING SYSTEMS OPERATE IN CONJUNCTION WITH ONE ANOTHER, AND MUST BE TESTED AS A COMPLETE SYSTEM. FOR CORRECT OPERATION OF STARTING/CHARGING SYSTEMS, ALL COMPONENTS USED IN THESE THREE SYSTEMS MUST PERFORM WITHIN SPECIFICATIONS. WHEN ATTEMPTING TO DIAGNOSE ANY OF THESE SYSTEMS, IT IS IMPORTANT THAT YOU KEEP THEIR INTERDEPENDENCY IN MIND.
CERTAIN STARTING SYSTEM COMPONENTS AND FUNCTIONS OF THE ESS SYSTEM ARE ON BOARD DIAGNOSTICS (OBD) II MONITORED AND WILL PRODUCE DIAGNOSTIC TROUBLE CODES (DTC). THE USE OF THE DIAGNOSTIC SCAN TOOL IS NOT ONLY RECOMMENDED, BUT IT IS NECESSARY FOR PROPER DIAGNOSIS OF THE ESS SYSTEM AND THE COMPONENTS OR SYSTEMS THAT ARE RELATED TO ESS SYSTEM FUNCTIONS.
ON ATX EQUIPPED VEHICLES THE PCM SENDS A SIGNAL TO TCM TO INDICATE IT IS READY FOR AN ESS EVENT. THE TCM RESPONDS IT IS READY FOR ESS AND ENTERS A HYDRAULIC NEUTRAL STATE WHILE IN AN AUTO-STOP EVENT AND STAYS IN HYDRAULIC NEUTRAL DURING THE AUTO-START EVENT TO AVOID VEHICLE MOVEMENT DURING ENGINE CRANKING.