2003 Honda Civic Fuel Pump Relay Location: A Complete Guide to Finding and Fixing It
The fuel pump relay on a 2003 Honda Civic is located behind the glove box, on the passenger side of the vehicle. This is the PGM-FI main relay 2, which controls power to the fuel pump. If your Civic cranks but won’t start, or you don’t hear the fuel pump prime when you turn the key, this relay is the first thing to check. Knowing exactly where it is and how to test it can save you time and money.
What Is the Fuel Pump Relay and Why Does It Matter?
The fuel pump relay is a small electrical switch that controls power delivery to the fuel pump inside your gas tank. When you turn the ignition key to the ON position, the relay engages for about two to three seconds to prime the fuel system. It stays engaged while the engine runs. If this relay fails, your fuel pump won’t receive power, and your engine won’t start or will stall unexpectedly .
On the 2003 Honda Civic, the fuel pump relay is part of a larger unit called the PGM-FI main relay. This unit actually contains two separate relays: one controls the fuel injectors, and the other controls the fuel pump. The relay that handles the fuel pump is specifically called PGM-FI main relay 2 .
Symptoms of a Bad Fuel Pump Relay on a 2003 Honda Civic
Knowing the warning signs can prevent you from being stranded. Here are the most common symptoms:
1. Engine cranks but won’t start. This is the most definitive sign. You turn the key, the starter motor works fine, but the engine never fires up because no fuel reaches the combustion chambers .
2. No fuel pump prime sound. When you turn the key to the ON position (without starting), you should hear a brief buzzing or whining sound from the rear of the car near the fuel tank. If you don’t hear this sound, the relay may not be sending power to the pump .
3. Intermittent stalling. The engine runs fine for a while, then suddenly dies without warning. After a few minutes, it might restart. This pattern strongly suggests a failing relay that works intermittently due to heat or vibration .
4. Engine surges while driving. If the relay makes intermittent contact, the fuel pump may receive power inconsistently, causing the engine to surge or hesitate during acceleration .
5. Check engine light comes on. The PCM (Powertrain Control Module) monitors the fuel pump circuit and may store diagnostic trouble codes related to fuel delivery issues .
Exact Location of the Fuel Pump Relay on a 2003 Honda Civic
The fuel pump relay on a 2003 Honda Civic is located behind the glove box, on the passenger side of the dashboard. This is consistent across most trim levels, including the LX, EX, and DX models .
To access it, follow these steps:
Step 1: Open the glove box fully.
Step 2: Remove the stoppers on each side of the glove box. These are small plastic pins that prevent the glove box from opening too far. You can usually press them inward or pull them out by hand.
Step 3: Let the glove box pivot downward. This will expose the area behind it.
Step 4: Look for a small cube-shaped relay. You will find two relays side by side. The one on the right is the PGM-FI main relay 2, which controls the fuel pump. The one on the left is the PGM-FI main relay 1, which controls the fuel injectors .
Important note: On some 2003 Civic models, the fuel pump relay is also accessible from the driver’s side under-dash fuse box. However, the most common and reliable location for the 2003 model year is behind the glove box .
How to Test the Fuel Pump Relay on a 2003 Honda Civic
Testing the fuel pump relay is straightforward and requires only a multimeter or a 12V test light. Here is a step-by-step procedure based on the 2002-2003 Honda Civic service manual :
Step 1: Locate and remove the relay. After opening the glove box and letting it pivot down, locate the PGM-FI main relay 2. Gently pull it out of its socket.
Step 2: Check for power at the relay socket. With the ignition switch turned ON, measure the voltage between terminal No. 5 of the relay connector and body ground. You should see battery voltage (around 12 volts). If not, there is an open circuit in the wire between the PGM-FI main relay 1 and the PGM-FI main relay 2 .
Step 3: Check for ignition power. Measure voltage between terminal No. 1 of the relay connector and body ground. With the ignition ON, you should see battery voltage. If not, there is an open circuit in the wire between the under-dash fuse/relay box and the PGM-FI main relay 2 .
Step 4: Check the control signal from the ECM. Turn the ignition OFF. Disconnect the ECM connector E (31P). Check for continuity between terminal No. 3 of the PGM-FI main relay 2 connector and terminal El of the ECM connector. You should have continuity. If not, repair the open wire between the relay and the ECM .
Step 5: Listen for the fuel pump. If all electrical checks pass, reinstall the relay and turn the ignition ON. You should hear the fuel pump prime for 2 seconds. If you don’t hear it, the relay itself may be faulty, or the fuel pump may have failed .
Quick Testing Method: Relay Swap
A simpler way to test the relay is to swap it with a known good relay from another circuit. Many 2003 Honda Civics have multiple relays with the same pin configuration. For example, you can swap the PGM-FI main relay 2 with the horn relay or the PGM-FI main relay 1. If the car starts after the swap, the original relay is bad .
Fuel Pump Fuse Location for 2003 Honda Civic
Before replacing the relay, check the fuel pump fuse. On the 2003 Honda Civic, the fuel pump fuse is located in the under-dash fuse box, which is underneath the steering column on the driver’s side. The fuse is labeled as number 17 in the fuse box diagram .
Open the fuse box cover by turning the knobs as shown in the diagram. Locate fuse number 17 (usually a 15A or 20A fuse). If the fuse is blown, replace it with a new one of the same amperage. If the new fuse blows immediately, there is a short circuit in the fuel pump wiring .
Replacing the Fuel Pump Relay on a 2003 Honda Civic
Replacing the fuel pump relay is a simple DIY task. The OEM part number for the 2003 Honda Civic fuel pump relay is 39794-S5A-003. This is a genuine Honda part that fits all 2003 Civic submodels, including the 2 Door DX, 2 Door EX, 2 Door HX, 2 Door LX, 3 Door SI, 4 Door DX, 4 Door EX, 4 Door GX, 4 Door LX, and 4 Door MX (Hybrid) .
Replacement steps:
Step 1: Disconnect the negative battery terminal. This prevents any accidental electrical shorts.
Step 2: Open the glove box and remove the stoppers. Let the glove box pivot downward.
Step 3: Locate the PGM-FI main relay 2 (the one on the right).
Step 4: Gently pull the relay straight out of its socket. Do not twist or pry it.
Step 5: Insert the new relay into the socket. Make sure it clicks into place.
Step 6: Reinstall the glove box by pushing it back up and reinserting the stoppers.
Step 7: Reconnect the negative battery terminal.
Step 8: Turn the ignition ON and listen for the fuel pump prime sound. If you hear it, the replacement was successful.
What If Replacing the Relay Doesn’t Fix the Problem?
If you have replaced the relay and the fuse, but the fuel pump still doesn’t work, the issue may be with the fuel pump itself. The fuel pump on a 2003 Honda Civic is located inside the fuel tank. You can access the top of it by removing the rear seat bottom cushion and then taking off a small metal service cover plate found underneath .
Signs that the fuel pump itself has failed:
- You hear no fuel pump prime sound even after replacing the relay
- The engine starts but runs poorly, hesitates, or stalls
- The fuel pressure is low (below 40-50 PSI) when tested with a gauge
Testing the fuel pump: Use a multimeter to check for voltage at the fuel pump connector under the rear seat. With the ignition ON, you should see battery voltage. If voltage is present but the pump doesn’t run, the pump is likely faulty and needs replacement .
Preventing Future Fuel Pump Relay Issues
The fuel pump relay on the 2003 Honda Civic is a known failure point, especially as the vehicle ages. The relay contains internal solder joints that can crack over time due to heat and vibration. Here are some tips to prevent future issues:
Use genuine OEM parts. Aftermarket relays may not have the same quality or durability. The genuine Honda part (39794-S5A-003) is recommended for the best fit and reliability .
Keep the fuse box clean. Moisture and corrosion can cause relay failure. Make sure the area behind the glove box is dry and free of debris.
Don’t run the fuel tank low. Running the tank near empty can cause the fuel pump to overheat, which can damage the relay and the pump itself .
Replace the relay proactively. If your Civic is over 15 years old, consider replacing the fuel pump relay as preventive maintenance. It’s a cheap part and easy to install.
Recommended Fuel Pump for Your 2003 Honda Civic
If you need to replace the fuel pump itself, we strongly recommend using a high-quality replacement. KEMSO Racing offers a range of fuel pump products that are designed for performance, reliability, and direct OEM replacement. Their fuel pumps come with a lifetime warranty, so you can install them with confidence knowing they are built to last.
KEMSO fuel pumps are engineered to meet or exceed factory specifications. They deliver consistent fuel pressure, which is critical for the 2003 Honda Civic’s fuel injection system. Whether you need a standard replacement or a high-flow pump for performance upgrades, KEMSO has the right solution for your vehicle.
Visit https://www.kemsoracing.com/ to browse their selection of fuel pumps and other performance parts. Their products are trusted by mechanics and car enthusiasts alike for their durability and performance.
Summary
The fuel pump relay on a 2003 Honda Civic is located behind the glove box, on the passenger side. It is the PGM-FI main relay 2, which controls power to the fuel pump. If your Civic cranks but won’t start, or you don’t hear the fuel pump prime, check the relay first. Testing it with a multimeter or swapping it with a known good relay will confirm if it’s faulty. Replacement is simple and inexpensive, with the OEM part number 39794-S5A-003 . Always check the fuel pump fuse (fuse number 17 under the dash) before replacing the relay . If the relay and fuse are both good, the fuel pump itself may need replacement.
For the best results, use genuine Honda parts or high-quality aftermarket replacements like those from KEMSO. Visit https://www.kemsoracing.com/ for reliable fuel pump solutions that come with a lifetime warranty.