Base Starting
DESCRIPTION
The standard starting system can consist of the following components:
| 1. | Refer to RADIO FREQUENCY HUB (RFH) MODULE . |
| 2. | Refer to KEYLESS IGNITION NODE (KIN) OR KEYLESS GO BUTTON . |
| 3. | Refer to BODY CONTROL MODULE (BCM) . |
| 4. | Refer to STARTER MOTOR RELAY - Located within the Power Distribution Center (PDC). |
| 5. | Refer to POWERTRAIN CONTROL MODULE (PCM) . |
| 6. | Refer to STARTER MOTOR . |
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.
The diagnostic procedures used in each of these groups include the most basic conventional diagnostic methods, to the more sophisticated On-Board Diagnostics (OBD) built into the PCM. Use of an induction-type milliampere ammeter, volt / ohmmeter, battery charger, carbon pile rheostat (load tester), and 12-volt test lamp may be required.
OPERATION
The starter is always operated by a single relay positioned in the PDC and activated by the PCM. The activation signal reaches the BCM, which will activate an internal relay of its own, which sends a signal to the relay located in the PDC and activated by the PCM. When the PCM activates the relay, a 12 volt feed arrives at the starter solenoid, which will activate the starter.
Starting System equipped with a RFH:
- Pressing the Keyless Ignition Node (KIN), a request is sent to the RFH via a private Local Interface Network (LIN) bus for authentication.
- The RFH receives the request from the KIN and then looks for the valid key fob by using the Low Frequency (LF) antennas.
- If the RFH detects a valid key fob and if the brake is engaged, the RFH sends a Controller Area Network (CAN) request to the BCM to change the ignition position to START/CRANK.
- Then the BCM sends the command to the PCM to turn the vehicle to CRANK.
- If conditions are correct to start, the PCM turns on the high side of the PCM starter relay and turns the Crank Hold Signal to True. If the BCM is still in crank and the Crank Hold is true then the BCM turns on the low side of the BCM Starter relay and the engine will start cranking.
- Once the engine is started the PCM deactivates the double start over ride.
- The BCM will then deactivate the starter either when the engine starts or the maximum time of 10 seconds has been reach for the tip start.
- The RFH changes the ignition position to RUN if the start type is TIP start or the five second time expires or the engine controller indicates the vehicle is not in park or neutral.
- The engine can be manually shut down by the driver with speeds over 8 km/h (5 mph) in any gear.
| Refer to COMPONENT INDEX . |
- The BCM is responsible for gating messages across the various bus networks.
- The BCM is responsible for actuating the low side of starter relay once commanded by the PCM high side relay CRANK command.
- The BCM communicates over the Local Interface Network (LIN) bus with the Intelligent Battery Sensor (IBS) information about raw battery current, voltage, and temperature levels
- The BCM is responsible for deactivating the starter motor relay driver.
| Refer to COMPONENT INDEX . |
- When the operator presses the Keyless Go button, the key fob is validated wirelessly by the RFH. If the key fob is recognized as belonging to the vehicle and is inside the vehicle, the system allows the ignition state of the vehicle to be changed by the operator between the ACCESSORY, RUN, and START ignition states.
- Used to broadcast the start button status.
Light Emitting Diode (LED) Indicator Operation:
The LEDs in the Keyless Go button provide visual indication of the ignition system and button use to aid the driver. The Logic for LED control is implemented in the RFH. The Keyless Go button contains four LEDs:
- OFF Indication
- ACC Indication (Accessory)
- ON Indication (ON or RUN)
- KIN switch indicator (button backlight)
The RFH will log a Diagnostic Trouble Code (DTC) indicating an incorrect ignition status value is present; in this state the ignition status is unknown. This will continue until the correct signal is received by the RFH.
| Refer to COMPONENT INDEX . |
- The PCM turns on the high side of the starter relay.
- The PCM turns the crank hold signal to true which enables the BCM to turn on the low side of the starter relay.
- The PCM disables the double start over ride once the engine is started.
| Refer to COMPONENT INDEX . |
- Receives the input request to start from the ignition.
- Energizes the key fob transponder in order to read it.
- Sends a random code to the transponder and in return, receives a crypt code from the transponder.
- Validates the key fob using LF antennas.
- Validates that the brake is engaged.
- Sends a request to the BCM to change the ignition state.
| Refer to COMPONENT INDEX . |
- Incorporates the starter solenoid.
- The starter consists of a Direct Current (DC) motor powered by the battery and an electromagnet exciter.
- The starter is operated by a single relay positioned in the PDC and activated by the PCM.
| Refer to COMPONENT INDEX . |
- The starter motor relay is commanded by the PCM and is used to enable the starter power circuit.