What is an asd relay dodge caravan?

In simple terms, an ASD relay (Auto Shutdown Relay) is a key electrical component that powers the engine’s ignition and fuel systems. If it fails, a Dodge Grand Caravan may crank but fail to start.

What the ASD relay does in a Grand Caravan

The ASD relay is controlled by the vehicle’s powertrain control module (PCM). When energized, it provides power to the ignition coils and fuel injectors, enabling the engine to run. The PCM can de‑energize the ASD relay in response to faults or safety conditions, effectively shutting down the engine to protect the vehicle and occupants. Because it sits at a critical junction between ignition, fuel delivery, and engine control, a faulty ASD relay is a common reason for a Grand Caravan that won’t start or that stalls unexpectedly.

Where to find the ASD relay

Location varies by year and model, but these are the most common spots you’ll encounter on a Dodge Grand Caravan. Use the following as a quick guide, and always verify with the manual or a parts diagram.

• Engine bay fuse/relay box near the battery


• Under-hood Power Distribution Center (PDC) on the driver’s side


• Under-dash fuse/relay box, sometimes near the steering column

Labels on the fuse box lid or a factory diagram inside the cover typically show the ASD relay’s position and part number.

Model-year notes

The exact spot can vary by year and trim level. If you’re unsure, start with the most accessible engine bay fuse/relay box and check the lid diagram or the service manual for your exact model year.

Signs the ASD relay may be failing

These symptoms commonly point to a faulty ASD relay, though they can also be caused by other issues in the ignition or fuel systems. If you notice several of these together, test the relay as part of your diagnosis.

• Engine cranks but does not start


• Engine starts and then stalls soon after


• No audible fuel pump priming when you turn the key to ON


• Intermittent loss of spark or fuel delivery while driving


• Difficulty starting that doesn’t improve with other basic fixes

Because symptoms overlap with other problems (bad ignition switch, faulty fuel pump, or sensor faults), testing the ASD relay should be part of a broader diagnostic check.

Testing and replacing the ASD relay

Testing the ASD relay is a practical, do‑it‑yourself task if you have basic tools. The simplest method is to swap in a known‑good identical relay from the same fuse box. If the symptoms disappear, the original relay is faulty. If the problem persists, the issue may lie elsewhere in the ignition/fuel system or in the PCM.

1. Safety first: disconnect the negative battery cable to prevent short circuits while you work.


2. Turn off the ignition and locate the ASD relay in the engine bay fuse/relay box, the PDC, or under-dash box (check the lid diagram).


3. Remove the ASD relay and inspect for signs of damage: melted plastic, corrosion, or burning smell.


4. Compare the relay with a known-good spare. Swap positions and attempt to start the engine.


5. If the engine starts with the swapped relay, replace the old one with a new identical ASD relay.


6. Reconnect the battery, clear any codes, and test drive. If problems persist, seek professional diagnostics (PCM, wiring, or sensor faults).

Note: Ensure you use the correct part number for your model year, as relays can look identical but have different coil ratings or pin configurations.

What to do if swapping the relay doesn’t solve the problem

If a known-good relay does not fix the no-start or stalling issue, the root cause may be elsewhere in the electrical or control system. Potential next steps include inspecting ignition switch wiring, the crankshaft/camshaft position sensors, fuel pump wiring, or PCM integrity. A professional diagnostic session can help isolate ECM/PCM faults or wiring harness problems.

Summary

The ASD (Auto Shutdown) relay in a Dodge Grand Caravan is a crucial component that gates power to the ignition and fuel delivery circuits under PCM control. When it fails, symptoms often include no-start, stalling, or intermittent running. Its exact location varies by year, but common spots include engine bay fuse/relay boxes and the Power Distribution Center. Diagnosis typically starts with symptom observation and a relay swap or electrical test, followed by replacement if needed. If issues persist, professional diagnostics are recommended to rule out PCM or related wiring faults.

What are the symptoms of a bad ASD relay?

Symptoms of a bad ASD (Automatic Shutdown) relay include the engine failing to crank, stalling while running, and the check engine light coming on. Other signs can be poor acceleration or the engine not starting immediately. A rapid clicking sound from the relay when the key is turned is often a sign of a faulty relay or an electrical issue it is connected to, such as the oxygen sensor circuit.
 
Common symptoms of a bad ASD relay

• Engine won't crank: The engine may not start at all when you turn the key, even though the dash lights come on. 
• Engine stalls: The vehicle may stall immediately after starting or randomly while driving. 
• Check Engine Light: The "check engine" warning light will often illuminate on the dashboard. 
• Poor acceleration or hesitation: The engine may lag or hesitate when you try to accelerate. 
• Intermittent starting issues: The car may start sometimes and fail to start at other times. 
• Clicking sound: You may hear a rapid clicking sound from the relay area, which can indicate a problem with the relay itself or a related circuit. 

What the ASD relay does
The Automatic Shutdown (ASD) relay controls power to some of the most critical components of the engine management system, including: ignition coils, fuel injectors, alternator, and fuel pump.

What is the purpose of the ASD relay?

The Auto Shutdown (ASD) Relay is a safety and control component in many vehicles that provides power to critical engine components like the fuel injectors, ignition coils, and alternator field. Its main function is to control the flow of power to these systems; it is often activated when the ignition key is turned and stays on as long as the engine's computer (PCM) detects the engine is running.
 
What the ASD relay does

• Provides power to essential components: The ASD relay delivers 12-volt power to the fuel injectors and ignition coils, which are necessary for the engine to start and run. It can also power the alternator field, which charges the battery. 
• Controls power based on engine signal: The relay is activated by the PCM, which grounds the control circuit for the relay when the engine is running. 
• Protects against engine stall: If a fault occurs, such as a faulty crankshaft position sensor, the PCM can cut power by removing the ground to the ASD relay, which will stop the engine and prevent further damage. 
• Handles high-load circuits: Relays are used in these applications because a low-power control signal from the PCM can safely switch on a much higher-power load, like the fuel pump and ignition system, without melting the switch. 

Symptoms of a failing ASD relay

• No-start condition: If the relay fails completely, the engine may not start because the fuel and ignition systems are not receiving power. 
• Intermittent stalling: A faulty relay can cause intermittent power loss, leading to the engine stalling randomly while driving. 
• Rough running or hesitation: A weak or failing relay might cause intermittent power delivery issues, resulting in hesitation during acceleration. 
• Starting issues: An engine may start but then stall almost immediately or fail to restart after being turned off. 

How do you test an ASD relay?

To test an ASD relay, you can test its power, ground, and control circuits using a multimeter or test light at the relay socket. First, check for constant power with the key off, then check for ignition-switched power with the key on, and finally, verify the computer-controlled ground when the engine is cranking. Alternatively, you can test the relay itself using an ohmmeter to check the coil resistance or a 12V battery to see if it clicks.
 
Using a multimeter at the relay socket 
This video demonstrates how to test an ASD relay for power and ground circuits: 58sBSK GarageYouTube · Jan 24, 2020

1. Locate the relay: Find the ASD relay in the fuse/relay box, often labeled on the box cover. 
2. Check for constant power: With the ignition off, use a multimeter or test light to check for constant power on one of the pins. A good relay socket will have constant power here. 
3. Check for ignition power: With the ignition turned to the "on" or "start" position, check for a second source of power. You should now have power on two pins: the constant power pin and the ignition-switched power pin. 
4. Test the ground: The computer controls the ground for the relay. Use an ohmmeter to check continuity from the relay's ground terminal back to the computer's ground point. You can also check for the presence of a ground signal (close to 000 volts) at the relay's ground terminal when the engine is cranking. 
5. Test the wiring: Use the ohmmeter to test for continuity and resistance in the wires connecting the relay to the fuse box, computer, and other components. High resistance can indicate a bad connection or damaged wire. 

Testing the relay itself
This video demonstrates how to test a relay with a multimeter: 1mElectro UniversityYouTube · Oct 21, 2022

1. Remove the relay: Disconnect the battery and remove the relay from the vehicle. 
2. Check the coil resistance: Set your multimeter to the ohms setting (200Ω200 cap omega200Ω is a good starting point). Touch the leads to the two coil terminals (usually pins 85 and 86). The resistance should be within the specified range, often between 50Ω50 cap omega50Ω and 200Ω200 cap omega200Ω. 
3. Simulate activation: You can manually connect the two coil terminals (85 and 86) to a 12V power source. The relay should click, indicating the coil is working. If it doesn't click, the coil is likely bad. 
4. Check the contacts: To test the normally open contacts, set your ohmmeter to continuity (beeps for connection, or a very low resistance) and check the contacts while manually actuating the armature or while power is applied to the coil. The resistance should drop to very low levels when the contacts are closed. 

What is a Dodge ASD relay?

The automatic shutdown (ASD) relay powers the ignition coils, fuel injectors, and alternator field in many Chrysler vehicles. If this part fails, the engine can stall, fail to crank, or lag while accelerating.