1999 Toyota Camry Fuel Pump Relay: Complete Guide to Location, Testing, and Replacement

If your 1999 Toyota Camry cranks but won't start, the fuel pump relay is often the first thing to check. The fuel pump relay on a 1999 Toyota Camry is actually called the Circuit Opening Relay (C/OPN) , and it is located in the engine compartment fuse and relay box, not under the dashboard. This relay controls power to the fuel pump, and when it fails, the pump receives no electricity, the engine gets no fuel, and your car simply will not start. Before you assume the fuel pump itself is bad, testing the relay is a quick, inexpensive diagnostic step that can save you hundreds of dollars.

What Is the Fuel Pump Relay and Why Does It Matter?

The fuel pump relay is an electrical switch that controls power to the fuel pump. When you turn the ignition key to the ON position, the engine computer (PCM) or the ignition switch triggers the relay, which then sends battery voltage to the fuel pump. The pump briefly runs for one or two seconds to pressurize the fuel system before the engine starts. If the relay is faulty, the pump stays silent, and the engine gets no fuel.

On the 1999 Toyota Camry, the relay is officially called the Circuit Opening Relay and is labeled "C/OPN" on the fuse box cover. It is a standard four-pin, 12V, 40A relay. Many owners mistakenly look for a "fuel pump relay" under the dash, but on this generation Camry, it lives in the engine bay.

Exact Location of the 1999 Toyota Camry Fuel Pump Relay

The fuel pump relay is located in the engine compartment relay box No. 1, which sits next to the battery on the driver's side of the engine bay. Here is how to find it:

  1. Open the hood and locate the main fuse and relay box on the driver's side, near the battery and air filter housing.
  2. Remove the black plastic cover from the fuse box. On the underside of the cover, you will find a label that identifies each relay and fuse.
  3. Look for a relay labeled "C/OPN" (Circuit Opening). This is your fuel pump relay.
  4. It is a small, rectangular, four-pin relay.

Some earlier online sources suggest the relay might be under the dashboard, but for the 1999 model year, the factory service manual and multiple verified repair sources confirm it is in the engine compartment fuse box.

How to Tell If Your Fuel Pump Relay Is Bad

A faulty fuel pump relay produces symptoms that are easy to mistake for a dead fuel pump or a bad fuse. Here are the most common signs:

  1. Engine cranks but does not start. This is the most common symptom. The starter motor turns the engine over, but there is no fuel delivery.
  2. No fuel pump noise. When you turn the key to the ON position (not START), you should hear a brief whirring sound from the rear of the car for about one to two seconds. If you hear nothing, the relay or pump is not getting power.
  3. Car starts then dies. A failing relay can intermittently cut power, causing the engine to start briefly and then stall.
  4. Engine stalls while driving. If the relay loses connection while you are on the road, the engine will suddenly die without warning.
  5. Check Engine Light comes on. The PCM detects a loss of fuel pressure or a circuit fault and illuminates the warning light.

Step-by-Step Guide to Testing the Fuel Pump Relay

Testing the relay is straightforward and requires only a multimeter or a 12V test light.

Step 1: Locate and remove the relay. Find the C/OPN relay in the engine compartment fuse box. Pull it straight out.

Step 2: Identify the pins. A standard four-pin relay has two pins for the control coil (pins 85 and 86) and two pins for the power switch (pins 30 and 87).

Step 3: Check the coil resistance. Set your multimeter to ohms (Ω). Touch the probes to pins 85 and 86. You should see a resistance reading typically between 50 and 120 ohms. If the reading is infinite (open circuit), the coil is burned out and the relay is dead.

Step 4: Test the switch contacts. With the relay still removed from the car, check continuity between pins 30 and 87. There should be no continuity (infinite resistance) because the switch is normally open.

Step 5: Apply power to the coil. Use jumper wires to connect pin 85 to battery negative and pin 86 to battery positive (12V). You should hear a distinct click. Now, check continuity between pins 30 and 87 again. This time, the circuit should be closed (near zero ohms). If you do not hear a click or the switch does not close, replace the relay.

What to Check Before Replacing the Relay

Before you buy a new relay, verify these simple things:

Check the EFI fuse. The fuel pump circuit is protected by the EFI No. 1 fuse, which is also located in the engine compartment fuse box. If this fuse is blown, the relay cannot send power to the pump. Pull the fuse and inspect the metal strip inside. If it is broken, replace it with a new one of the same amperage.

Check for voltage at the relay socket. With the relay removed, turn the ignition to ON. Use a test light or multimeter to check for battery voltage at one of the socket terminals (the one corresponding to pin 30). If there is no voltage, the problem is upstream: a blown fuse, a bad EFI main relay, or a wiring issue.

Check the fuel pump ground. If the relay clicks and the fuse is good, but the pump still does not run, the fuel pump itself may have failed, or the ground wire at the pump may be corroded.

How to Replace the 1999 Toyota Camry Fuel Pump Relay

Replacing the relay is simple and takes about five minutes.

  1. Purchase a replacement relay. The OEM part number is 90987-03003 (also cross-referenced as 156700-0130). This is a standard 12V, 40A, four-pin relay that fits many Toyota models from 1992 to 2001.
  2. Open the engine compartment fuse box.
  3. Locate the C/OPN relay and pull it straight out.
  4. Plug the new relay into the same socket. It will only fit one way.
  5. Replace the fuse box cover.
  6. Turn the ignition to ON and listen for the fuel pump to prime for one to two seconds.

Why the Fuel Pump Relay Fails

Relays are electromechanical parts, and they wear out over time. The internal coil can burn out, or the switch contacts can become pitted or corroded from repeated arcing. High mileage, age, and exposure to engine bay heat all contribute to failure. If your 1999 Camry has over 100,000 miles, the relay is a good candidate for replacement even if it is still working, as a preventive measure.

The Best Upgrade for Your Fuel System: KEMSO Fuel Pump

While the relay is a common failure point, the fuel pump itself is another component that can fail on a 1999 Camry, especially after 150,000 miles. When you replace the pump, you want a part that is reliable, durable, and backed by a solid warranty. That is where KEMSO comes in.

KEMSO fuel pumps are high-performance, OEM replacement units designed to meet or exceed the original factory specifications. Every KEMSO fuel pump is built with quality materials and rigorous testing standards to ensure long-lasting performance. Whether you drive a 1999 Camry with the 2.2L 5S-FE engine or any other compatible vehicle, KEMSO has a pump that fits perfectly.

Why choose KEMSO?

  • OEM Replacement Quality: Direct fit, no modifications needed. The pump drops right into your existing fuel pump assembly.
  • High Performance: Engineered to deliver the correct fuel pressure and flow rate for your engine.
  • Lifetime Warranty: KEMSO stands behind its products. Every fuel pump comes with a lifetime warranty, so you are covered for as long as you own your vehicle.

To browse the full selection of KEMSO fuel pumps for your 1999 Toyota Camry and other vehicles, visit: https://www.kemsoracing.com/

Final Thoughts

The 1999 Toyota Camry fuel pump relay (C/OPN relay) is a small, inexpensive part that can cause a big headache when it fails. It is located in the engine compartment fuse box, next to the battery. Testing it takes only a few minutes with a multimeter, and replacement is a simple plug-and-play job. Always check the relay and the EFI fuse before condemning the fuel pump itself. If you do need to replace the fuel pump, consider upgrading to a KEMSO fuel pump for reliable performance and a lifetime warranty.

For more information and to find the right fuel pump for your 1999 Toyota Camry, visit https://www.kemsoracing.com/


Back to blog