- Electronic control module (ECM).
- Crank position sensor (CKP).
- Manifold absolute pressure sensor (MAP).
- Intake air temperature sensor (IAT).
- Engine coolant temperature sensor (ECT).
- Idle air control (IAC).
- Throttle position sensor (TP).
- Vehicle speed sensor (VSS).
- Turn signal module (TSM) or optional factory-installed turn signal security module (TSSM). This includes an integrated bank angle sensor (BAS).
- Fan relay.
- System relay.
- Ignition (plug top) coils.
- Purge solenoid (California models only).
The ECM is mounted ahead of the battery behind the left side cover. It computes the spark advance for proper ignition timing and fuel control based on sensor inputs (from CKP, MAP and TP sensor) and controls the low-voltage circuits for the ignition coils and injectors. The Scanalyzer can access the data received by and stored in the ECM.
The ECM contains all of the solid state components used in the ignition system. The dwell time for the ignition coil is also calculated in the microprocessor and is dependent upon battery voltage. The programmed dwell is an added feature to give adequate spark at all speeds. (The ECM has added protection against transient voltages, continuous reverse voltage protection, and damage due to jump starts.) The ECM is fully enclosed to protect it from vibration, dust, water or oil. This unit is a non-repairable item. If it fails, it must be replaced.
The crank position sensor (CKP) is located on the left front of the lower crankcase half. The CKP generates an AC signal which is sent to the ECM where it is used to reference engine position (TDC) and speed. It functions by taking readings off the 22 teeth on the alternator rotor (two teeth are missing to establish a reference point).
The MAP sensor is located on top of the front intake manifold. The MAP sensor monitors the intake manifold pressure (vacuum) and sends the information to the ECM where the module adjusts the spark and fuel timing advance curves for optimum performance.
The bank angle sensor is within the turn signal/turn signal security module. If the vehicle lean angle exceeds 45 degrees, the ignition system is shut off. Once the sensor is tripped, the motorcycle must be uprighted, turned off and then on again before the engine can be restarted. This is communicated across the data link.
Front and rear coils fire each spark plug independently (one cylinder at a time - no wasted spark). The coil also has an extra terminal to monitor current on the coil secondary circuit. This is used for knock detection and combustion diagnostics.
The ignition system gives a spark near top dead center for starting. At rpm and loads above this, the system gives a spark advance that varies between 0° and 50°.
The IAT, ECT and TP sensors are used to provide information to the ECM to fine tune spark and fuel delivery. The engine coolant temperature (ECT) sensor also controls the cooling fan relay that provides 12vdc to the fans. The VSS is used as an input for idle speed control.
The purge solenoid (California models only) allows vapors from the charcoal canister to flow to the throttle body. The timing and amount of solenoid opening depends on engine speed.
Note. On models not equipped with a purge solenoid, a resistive plug (Part No. 72529-01) is installed in the purge solenoid connector [95B] to prevent an error message being generated.
Troubleshooting
See the VRSCA Electrical Diagnostic Manual for troubleshooting and diagnostic information.
![](https://motoinstruction.ru/img/harley/2/111260.jpg)
Figure 9-1. EFI system circuit