How To Reset ASD Relay: A Comprehensive Diagnostic And Troubleshooting Guide

The Automatic Shutdown (ASD) relay cannot be physically reset using a switch or manual adjustment because it is an electromechanical component governed by the Powertrain Control Module (PCM). To clear an ASD-related fault condition, you must diagnose the underlying triggering code, relieve system pressure, and cycle the ignition or disconnect the battery to reset the vehicle computer logic.

Pre-Operation & Equipment Checklist

Proper diagnosis and reset procedures for an Automatic Shutdown relay system require a methodical approach to avoid electrical damage and ensure personal safety. The ASD relay is a vital safety and operational component found primarily in Chrysler, Dodge, Jeep, and RAM vehicles. It controls power to the fuel injectors, ignition coil, fuel pump, and oxygen sensor heaters. When a fault occurs, the PCM trips the circuit open to prevent fuel flooding or fire hazards in the event of an engine stall or collision.

• Essential Gear, Tools, and Materials:
  
  
  • Digital Multimeter (DMM) capable of measuring DC voltage and continuity.
  • OBD2 Diagnostic Trouble Code (DTC) scanner with live data capabilities.
  • Basic hand tools including a 10mm wrench or socket set for battery terminal disconnection.
  • Replacement automotive relay matching exact OEM amperage ratings (typically 30A to 40A).
  • Safety glasses and insulated gloves.
• Mandatory Prerequisite Knowledge and Standards:
  
  
  • Basic understanding of automotive 12-volt DC electrical circuits, fusing, and relay switching logic (pins 30, 85, 86, and 87).
  • Familiarity with OBD2 scanning protocols and diagnostic flowchart interpretation.
• Estimated Budget and Duration Benchmarks:
  
  
  • Diagnostic and reset time: 20 to 45 minutes.
  • Material cost (if relay replacement is required): 15 to 40 USD.

Step-by-Step ASD Relay Diagnostic and Reset Workflow

Step 1: Scan and Record Diagnostic Trouble Codes

Connect your OBD2 scanner to the data link connector (DLC) located beneath the driver-side dashboard. Turn the ignition key to the ON position without cranking the engine. Run a full system scan to retrieve all stored, pending, and permanent diagnostic trouble codes. Pay close attention to codes such as P0351 through P0358 (ignition coil circuits), P0201 through P0208 (fuel injector circuits), or manufacturer-specific codes like P1495 or P1296 related to ASD control circuit performance. Write down all codes before clearing them.

Warning: Never backprobe sensitive PCM wiring harnesses with oversized test probes, as this can widen terminal pins and cause intermittent open circuits.

Step 2: Clear the Powertrain Control Module Memory

Once you have documented the active fault codes, use the OBD2 scanner interface to clear the memory codes from the PCM. If the underlying fault has been transient—such as a temporary voltage drop or a loose battery terminal—clearing the code will allow the computer to command the ASD relay closed upon the next key cycle. If the fault code immediately returns upon turning the key to the ON position, a hard electrical short or open circuit exists in the control circuit, and clearing the code alone will not resolve the issue.

Step 3: Perform a Hard Electrical Reset

If the PCM refuses to energize the ASD relay and no scanner is available, perform a hard system reset to drain residual capacitor voltage from the vehicle computers. Turn off the ignition completely. Use a 10mm wrench to loosen and remove the negative (-) battery terminal. Wrap the terminal in a clean shop towel to prevent accidental contact with grounded metal surfaces. Wait a minimum of 15 to 20 minutes to allow all electronic control modules to completely power down and lose volatile memory cache. Reconnect the negative battery terminal and torque it securely.

Pro-Tip: Turning on the headlights while the battery is disconnected can accelerate the depletion of residual electrical charge stored within vehicle module capacitors.

Step 4: Verify Relay Operation and Circuit Integrity

Locate the Power Distribution Center (PDC) or under-hood fuse box and find the ASD relay by referencing the diagram printed on the underside of the cover. Pull the relay straight up out of its socket. Inspect the terminal blades for signs of thermal discoloration, corrosion, or melting. Use your multimeter to test the relay coil continuity across pins 85 and 86, and check for proper switching continuity between pins 30 and 87 when 12 volts are applied. Swap the ASD relay with an identical auxiliary relay in the fuse box (such as the horn or AC compressor relay) to test if the problem migrates.

ASD Relay Specifications and Troubleshooting Parameters

Common ASD Relay Failures and Field Fixes

• Root Cause: Internal relay contact points become carbon-pitted and oxidized due to high inductive kickback from fuel injectors and ignition coils over high mileage.
  
  
  • Actionable Fix: Replace the faulty electromechanical relay with an OEM-spec replacement unit. Inspect the PDC cavity for terminal spread or heat damage.
• Root Cause: Corroded or loose wiring harness ground path between the PCM and the ASD relay control circuit.
  
  
  • Actionable Fix: Locate the main engine and chassis ground straps, remove them, clean the mounting surfaces down to bare metal with a wire brush, and re-torque securely.
• Root Cause: Intermittent short-to-ground in the downstream wiring harness running from the ASD relay output terminal to the fuel injectors or ignition coils.
  
  
  • Actionable Fix: Perform a visual inspection of the harness where it passes near sharp metal brackets or exhaust manifolds. Repair chafed wires with heat-shrink butt connectors and wrap with high-temperature loom.
• Root Cause: Internal failure of the Powertrain Control Module internal driver circuit that supplies the switched ground to the ASD relay.
  
  
  • Actionable Fix: Verify all input power and ground feeds to the PCM. If verified and the driver remains dead, repair or replace the PCM and flash with appropriate software.

Frequently Asked Questions

What are the primary symptoms of a failing ASD relay?

A failing ASD relay typically causes a crank-no-start condition where the engine cranks normally because the starter circuit is separate, but it will not fire because fuel and spark are disabled. The engine may also mysteriously stall while driving and refuse to restart until the electrical system cools down.

Can I drive my vehicle with a bypassed or jumpered ASD relay?

Bypassing the ASD relay by running a jumper wire across high-current terminals is extremely dangerous and not recommended for normal operation. The ASD relay serves as an emergency safety cutoff designed to kill fuel and ignition if the engine stalls during an accident, preventing fuel pump pressurization into a compromised engine bay.

Where is the ASD relay located on most vehicles?

The ASD relay is almost always housed inside the main under-hood Power Distribution Center (PDC) alongside high-amperage fuses and other system relays. The exact slot location and label abbreviations vary by manufacturer, but consult the fuse box cover diagram or your specific vehicle service manual for precise identification.

Why does my ASD relay keep clicking rapidly?

Rapid clicking of the relay usually indicates low system voltage, a weak battery, a poor ground connection, or a failing ignition switch sending erratic signals to the PCM control circuit. Check system voltage with a multimeter and ensure all battery and starter cables are clean and tight.

Ensure long-term vehicle reliability by maintaining clean electrical connections and replacing aging electromechanical relays before they fail completely. If persistent electrical faults continue to plague your powertrain management system, consult a certified automotive technician equipped with factory-level diagnostic software.