Power Supply: Notes

Fig 1: Identifying Power Supply

KL30 - Battery Voltage:  B+ is the main supply of operating voltage to the ECM.

Power Supplies:  The power supplies (KL15 and ECM Relay) are fused to the MS42/MS43 ECM. The fuses are housed in the Engine Fuse Block located in the Electronics Box.

KL15 - Ignition Switch:  When the ignition is switched "on" the ECM is informed that the engine is about to be started. KL15 (fused) supplies voltage to the Engine Control Module Relay and the Fuel Injector Relay. Switching KL15 "off" removes the ECM operating voltage.

Fig 2: Identifying Ignition Switch Circuit

Engine Control Module Relay:  The ECM Relay provides the operating voltage for:

1. ECM 
2. Fuel Injection 
3. Idle Air Actuator 
4. Evaporative Emission Valve 
5. Fuel Pump Relay 
6. Ignition Coils 
7. Evaporative Leak Detection Pump 
8. Camshaft Sensors 
9. Hot Film Air Mass 
10. Oxygen Sensor Heaters 

Ground:  Multiple ground paths are necessary to complete current flow through the ECM. The ECM ground pin numbers are:

• Connector X60001 
• Connector X60005 
• Pin 4 - Ground for ECM 
• Pin 5 - Ground for ECM 
• Pin 5 - Ground for ECM 
• Pin 6 - Ground for ECM (MS42) 
• Pin 6 - Ground for ECM