The ASD relay, also known as the Automatic Shutdown Relay, is a crucial component of modern vehicle engines’ fuel and ignition systems. The ASD relay transmits power to the ignition coils and fuel injectors, allowing for spark production and fuel pumping. This article aims to educate you on the ASD relay’s function, the tools required to bypass it, the step-by-step process of bypassing it, and the pros and cons of doing so.
Understanding ASD Relay Function
The ASD relay is connected to the battery voltage through terminal number 30, which is always connected to the battery for both the fuel pump and the automatic shutdown relay. When the powertrain control module (PCM) grounds the ASD relay through terminal 85 and supplies voltage to the coil side of the ASD relay through terminal 86, the ASD relay is activated. In an off position, terminal 30 connects to terminal 87A, and when the fuel pump and automatic shutdown relay are powered, terminal 30 connects to terminal 87, supplying voltage to the remaining circuit.
When the vehicle’s engine is running, the automatic shutdown relay provides 12+ volts of switched power to the ignition coil and fuel injectors. The ASD relay also provides 12+ volts of power to the oxygen sensor heater relay and sensor heating elements. The power control module controls the circuit within the ASD relay, and when the PCM switches the circuit on or off, it simultaneously starts or stops the automatic shutdown relay operation.
When to Bypass ASD Relay and Tools Required
There are several symptoms of a faulty ASD relay, including engine stalling when it starts, a check engine light illuminating, and the engine failing to convert power into motion. To bypass the ASD relay, you will need a 12V DC 120 Amp 4 pin, plier, four pins 40/30 AMP 12 VDC harness, screwdriver, and other mechanic tools.
Step-by-Step Guide on How to Bypass ASD Relay
- Open the power module of your vehicle that houses the ASD relay and spring close the contact in the spring section if your vehicle’s coil is not powered up at that time.
- Energize the coil of your vehicle to create a flexible contact that allows current to flow and prepares the other contact.
- Locate the path that allows current flow below the relay and remove the fuel pump, replacing it with an electric fan. Place a jumper on pins #87 and #30 to bypass the automatic shutdown relay.
Pros and Cons of Bypassing ASD Relay
Bypassing the ASD relay is a safe move and will not damage your vehicle if done properly. The power will still run through the stock wires, and the engine circuit was originally made to receive the full voltage of the stock pump. However, the long-term effect of bypassing the ASD relay is uncertain and may reduce the engine’s lifespan. It is recommended to replace old wiring systems and rewire your car for better engine performance.
