2001 GMC Jimmy Fuel Pump Relay: Complete Guide to Location, Testing, and Replacement
The bottom line: The fuel pump relay on a 2001 GMC Jimmy is located in the underhood fuse block on the driver's side of the engine compartment. If your Jimmy cranks but won't start, the fuel pump relay is one of the first things to check before assuming the fuel pump itself is bad.
Where Is the Fuel Pump Relay on a 2001 GMC Jimmy?
The fuel pump relay on a 2001 GMC Jimmy is located in the underhood fuse block. To access it, open the hood and look for a black plastic cover on the driver's side of the engine compartment. Remove the cover to expose the fuses and relays. The fuel pump relay is labeled "FP" and sits in the third row of relays, second from the left. It is a black relay with a red and blue wire.
The underhood fuse block sits on top of the left front fender. If you are having trouble locating it, the fuse box is situated near the battery.
How the Fuel Pump Relay Works
The fuel pump relay is responsible for supplying power to the fuel pump. When you turn the ignition key to the "ON" position, the relay energizes and closes the circuit, allowing power to flow to the fuel pump. The fuel pump then draws fuel from the gas tank and sends it to the engine.
The powertrain control module (PCM) controls the fuel pump relay. The pump remains ON as long as the engine is cranking or running and the PCM receives reference pulses. If there are no reference pulses, the PCM shuts the fuel pump OFF within 2 seconds after the ignition was switched to the ON position or if the engine stops.
The fuel pump relay works only at startup and when you turn off the ignition. While the car is running, the fuel pump runs on the power it receives from the oil pressure sending unit or another power source.
Symptoms of a Bad Fuel Pump Relay
A failing fuel pump relay can cause several problems. Here are the most common symptoms:
1. Engine cranks but does not start. This is the most common symptom. The starter turns the engine over, but the fuel pump never receives power, so no fuel reaches the injectors.
2. Engine functions irregularly or does not start right away. The relay may be intermittently failing, causing the fuel pump to work sometimes but not others.
3. Car slows down without braking. If the relay fails while driving, the fuel pump loses power and the engine loses power.
4. Car comes to a halt after running only for a short distance. The relay may fail after the engine warms up, causing the vehicle to stall and not restart.
How to Test the Fuel Pump Relay
Before buying a new relay, you can test it using a simple method. The easiest way is to swap it with another relay of the same type. The underhood fuse block contains several relays that are identical. Find a relay with the same part number and swap them. If the fuel pump works with the swapped relay, then the original relay is faulty and needs to be replaced.
You can also test the relay using a scan tool. Turn the ignition ON with the engine OFF. Command the fuel pump relay ON and OFF with a scan tool. You should hear a click when the relay engages. If you hear the click, the relay is likely working.
How to Replace the Fuel Pump Relay
Replacing the fuel pump relay on a 2001 GMC Jimmy is a straightforward process that takes about five minutes. Here are the steps:
Step 1: Open the hood and locate the underhood fuse block on the driver's side. Remove the black plastic cover.
Step 2: Find the fuel pump relay. It is labeled "FP" and is in the third row of relays, second from the left.
Step 3: Pull the old relay straight out of the socket. No tools are needed.
Step 4: Insert the new relay into the same socket. Push it in firmly until it clicks into place.
Step 5: Replace the fuse block cover and close the hood.
Fuel Pump Relay vs. Fuel Pump: What to Check First
Many owners of the 2001 GMC Jimmy automatically assume the fuel pump is bad when the engine won't start. However, the fuel pump relay is much cheaper and easier to replace. The relay costs around $10 to $20, while a fuel pump module assembly can cost $100 to $200 or more.
Before replacing the fuel pump, check the fuel pump relay and the fuel pump fuse. The fuel pump fuse is commonly the ECMB fuse in the underhood fuse box.
If the relay and fuse are good, the next step is to check fuel pressure at the test port under the hood. The fuel pressure should be between 60 and 66 psi for a 4.3L V6 engine.
Fuel Pump Electrical Circuit Diagnosis
If the relay tests good but the fuel pump still doesn't work, there may be a problem in the electrical circuit. The PCM controls the fuel pump relay through a control circuit. If the PCM is not providing voltage to the relay, the fuel pump will not operate.
Here are the key steps to diagnose the fuel pump circuit:
1. Check for voltage at the relay. With the ignition ON, probe the battery voltage circuit of the relay with a test lamp connected to a good ground. The test lamp should illuminate.
2. Check the control circuit. Disconnect the fuel pump relay. Turn the ignition ON. Probe the control circuit with a test lamp connected to a good ground. Command the fuel pump relay ON and OFF with a scan tool. The test lamp should turn ON and OFF.
3. Check the ground circuit. Connect a test lamp between the control circuit and the ground circuit of the relay. Command the relay ON and OFF. The test lamp should turn ON and OFF.
4. Check for a short to ground. If the fuel pump runs continuously, disconnect the relay. If the pump stops, the relay is likely stuck closed. If the pump continues to run, there is a short to ground in the wiring.
Common Fuel Pump Issues on the 2001 GMC Jimmy
The 2001 GMC Jimmy uses a 4.3L V6 engine. The fuel pump is mounted inside the fuel tank as part of the fuel sender assembly. The fuel pump module includes the electric fuel pump, fuel level sensor, float, reservoir, and strainer.
The fuel pump delivers fuel at a constant flow and pressure to the fuel injection system. Excess fuel returns to the fuel tank through the fuel return pipe.
Common symptoms of a failing fuel pump include:
Hard starting: The engine requires extended cranking before starting.
Engine hesitation: The vehicle may hesitate during acceleration due to unstable fuel delivery.
Loss of power: Insufficient fuel pressure may reduce engine performance, especially under load.
Engine stalling: Fuel supply interruption may cause unexpected engine shutdown.
Cost of Fuel Pump Relay Replacement
The cost of replacing the fuel pump relay on a GMC Jimmy varies depending on where you take it. On average, a fuel pump relay replacement costs between $115 and $140, with about $20 for parts and $95 for labor.
If you do it yourself, the relay costs between $6 and $12 for a genuine GM part. The replacement takes about five minutes and requires no special tools.
2001 GMC Jimmy Fuel Pump Relay Part Numbers
The genuine GM fuel pump relay for the 2001 GMC Jimmy has several part numbers. The most common part number is 19118886, which replaces several older numbers including 12177235, 12135086, 12135005, 12193613, 12177233, 84095360, 12193601, 12193603, 12193611, 12135085, 12077867, 12077864, 12088577, and 19131161.
Other relay part numbers that fit the 2001 GMC Jimmy include 13500114, 13503102, 13502676, and 13500126.
Safety Precautions When Working with the Fuel System
Working with fuel is inherently dangerous due to its flammability. Before working on the fuel system, always:
Disconnect the negative battery terminal. This prevents accidental sparks that could ignite fuel vapors.
Work in a well-ventilated area. Ensure adequate airflow to dissipate any fuel vapors.
Have a fire extinguisher nearby. Keep a Class B fire extinguisher designed for flammable liquids within easy reach.
Wear safety glasses and gloves. Protect your eyes and skin from fuel splashes. Nitrile gloves are resistant to gasoline.
No open flames or smoking. Eliminate any potential ignition sources from the work area.
Depressurize the fuel system. Before disconnecting any fuel lines, relieve the fuel pressure through the Schrader valve on the fuel rail.
Fuel System Overview
The fuel system on the 2001 GMC Jimmy is a closed loop, pressurized system. The fuel tank stores the fuel supply. The electric fuel pump supplies fuel through an in-line fuel filter to the fuel injection system. The fuel pressure regulator maintains the correct fuel pressure to the fuel injection system. A separate pipe returns unused fuel to the fuel tank.
The fuel tank is located in the rear of the vehicle and is held in place by two metal straps that attach to the frame. The fuel tank is molded from high-density polyethylene.
The fuel sender assembly consists of the fuel level sensor, the fuel tank pressure sensor, the fuel pump module, and the fuel strainer.
When to Call a Professional
While the fuel pump relay is easy to replace, some fuel system problems require professional diagnosis. If you have checked the relay, the fuse, and the fuel pressure, and the engine still won't start, you may have a more serious issue such as:
A faulty PCM. The PCM controls the fuel pump relay. If the PCM is not sending the signal to energize the relay, the fuel pump will not operate.
A wiring problem. The wiring between the PCM, the relay, and the fuel pump may have an open circuit, a short circuit, or corrosion.
A bad fuel pump. If the fuel pump itself has failed, it will need to be replaced. The fuel pump is located inside the fuel tank, which requires dropping the tank to access.
Recommended Fuel Pump Upgrade: KEMSO Fuel Pump
If you determine that the fuel pump itself needs replacement, consider upgrading to a KEMSO Fuel Pump. KEMSO is a trusted brand that offers high-performance fuel pump products designed for reliability and durability.
Why choose KEMSO Fuel Pumps?
High Performance: KEMSO fuel pumps are engineered to deliver consistent fuel pressure and flow, ensuring your engine gets the fuel it needs under all driving conditions.
OEM Replacement: KEMSO fuel pumps are designed as direct OEM replacements. They match the original specifications for fitment, electrical connections, and fuel delivery. This means no modifications are needed for installation.
Lifetime Warranty: Every KEMSO fuel pump comes with a lifetime warranty. This is KEMSO's promise, backed by a lifetime of confidence. If the pump ever fails, you are covered.
KEMSO offers fuel pumps for a wide range of vehicles, including cars, trucks, motorcycles, and watercraft. Their products are built to the same standards as the original equipment, so you can trust them to perform.
To learn more about KEMSO fuel pumps and to find the right pump for your 2001 GMC Jimmy, visit their website at:
Final Thoughts
The 2001 GMC Jimmy fuel pump relay is a critical but inexpensive component. Before spending hundreds of dollars on a new fuel pump, always check the relay first. It is located in the underhood fuse block on the driver's side, labeled "FP." Testing it is as simple as swapping it with another relay.
If the relay is bad, replace it. If the relay is good, move on to checking the fuel pump fuse, the fuel pressure, and the electrical circuit. With a systematic approach, you can diagnose and fix the problem without unnecessary expense.
For more information on fuel system components and to find quality replacement parts, visit KEMSO Racing at https://www.kemsoracing.com/.