Your vehicle’s ECM and fuel pump relay are connected as the fuel pump relay receives power from ECM.
So, if you’re experiencing no power from ECM to fuel pump relay, there are several reasons.
The primary reason behind no power from ECM to the Fuel pump relay can be due to a bad ECM. This means the ECM is faulty or its connectors are corroded or damaged. Apart from that, it can be a blown fuse box or failed fuse issue. Also, the ignition switch is having some problems and needs a fix. Well, test the ECM for any issues, check the ground wire connections, and the ignition fuses.
No need to worry as I will guide you to an in-depth discussion on how to fix the issue. Keep reading to find out the reasons and solutions.
No Power From ECM to Fuel Pump Relay: Causes & Solutions
Well, there are several reasons for the ECM or fuel pump relay to go bad. So, let’s first look at the problems and troubleshoot options.
|For failed fuse, replace it.
|No Signal from the Ignition Switch
|Check the ignition fuses for any wiring issues. Also check for any damages to the pins and wiring, and replace it.
|Bad Ground Wire Connections
|Clean the damaged or dirty connectors and wires or replace them.
|Damaged Fuse Box
|Check for damaged or corroded wiring. Then clean the fuse box pins and connectors or replace the fuse box.
|Clean the ECM pins and connectors and replace the ECM.
So, now that you had a brief glimpse at the possible problems and troubleshooting options, let’s go deeper into the solutions.
There are several fuses within the fuel pump relay and the ECM that go from the ignition switch to the injectors. Failed fuses are common causes of any electrical issues in your car.
- Engine stalling or bad idling.
- Bad acceleration.
- Engine is not starting.
Follow the steps for any fuse issues.
Step 1: Locate the fuse in the fuse box underneath the steering or check the owner’s manual.
Step 2: Check all the fuse within the fuse box, especially the ones related to the fuel pump relay.
Step 3: Replace the failed fuses with the accurate rating for damage avoidance.
No Signal from the Ignition Switch:
The fuel pump relay gets power from the ECM and then a signal from the ignition switch to function. So, the fuel pump relay is not getting power because one of these conditions is not working.
- Engine stalls while driving.
- No power.
- Engine not starting.
Follow the following steps to fix the issue with the ignition switch.
Step 1: Check if the fuel pump is getting power from the ignition switch by testing the pins. Follow the car’s wiring diagram on the cover of the fuse box to identify which pins to test.
Step 2: Turn the ignition on. If the current is not coming to the fuse after the test the issue is with the wiring.
Step 3: Check for damages in the wiring. If so, replace the ignition switch. You’ll have to spend $200-$250 for the replacement including labor costs.
Damaged Fuse Box:
The fuel pump relay is located in the fuse box within the engine bay. The fuse box holds all the fuse for the electronics and protects them. So, damaged fuse boxes lead to ECM and fuel pump relay power problems.
- No electricity throughout the vehicle.
- Some blown fuse will cause the engine to stall or shut off.
Step 1: Disconnect the negative battery terminal and check the fuse box for water damage. If so, replace it.
Step 2: If not, check the wiring diagram and the pins related to the fuel pump relay, ground, and power.
Step 3: Clean the pins and connectors on both sides of the fuse box with WD-40. Let them dry up and start the car then.
Bad Ground Wire Connection:
The ground is what completes the electric circuit and holds the link between electric systems and electricity. The symptoms of bad ground wire connections are the same as before. Let’s dive into the solution.
Step 1: So, identify the pin for the fuel pump relay on the ground connection.
Step 2: Set the multimeter to resistance or ohm to test the pin. The ground connection is bad if the multimeter doesn’t show zero.
Step 3: Check for damages, loose or dirty connections in the wires from the ground pin.
Step 4: For loose or dirty ground wires, remove and clean them with WD-40 spray and tighten it. And for damages replace them.
So, ECM sends power to the fuel pump relay and the fuel pump relay then directs the power to the fuel pump. So, if you’re experiencing no power to fuel pump relay, it might be a bad ECM issue.
- Check engine light sign.
- Engine stalling or misfires or rough shifting or shuts off.
- Fuel pump relay is quiet.
- Rough acceleration.
- Fuel economy loss.
First, you need to clean the connectors and pins first for corroded ECM connections. Let’s see how.
Step 1: Disconnect the negative terminal of the battery and then the ECM.
Step 2: Spray electrical cleaners (WD-40 etc.) into the connectors and pins.
Step 3: Scrub the pins and connectors of ECM with a thin wire pipe brush or toothbrush. Try not to bend the pins while you’re at it.
Step 4: Allow the pins and connectors to dry and then reconnect the ECM and battery.
Step 5: Start the car and see if the ECM power relay comes back on.
If cleaning doesn’t work and you don’t want a used ECM for replacement, replace it with a new one. It will cost you $500-$1000. But I wouldn’t advise it as ECMs rarely cause major problems. So, buying a used ECM should not be an issue and it’s much cheaper.
Frequently Asked Questions (FAQs):
How Long Can You Drive With A Bad ECM?
Yes, you can drive with a bad ECM. But not for long depending on the failure issue. Which part of the ECM circuit failed and how, are the major concerns here.
How Long Can You Drive With A Bad Fuel Pump?
You can drive less than 100,000 miles with a bad fuel pump depending on how bad is the issue. For a serious fuel pump issue, you might expect 45,000 miles or even less.
Does A Fuel Pump Run All The Time?
Yes, a fuel pump runs all the time, even when the engine and ignition are off. But that doesn’t mean your fuel is wasted. Fuel pumps depend on fuel pump relay to function.
So, now you know why there is no power from ECM to fuel pump relay and how to fix the issue. Hope this article solves all your problems relating to ECM and fuel pump relay power problems. And do be careful as the fixes involve electrical parts and wiring.