2009 Cadillac CTS Fuel Pump Control Module Location: Where to Find It and How to Troubleshoot

If you own a 2009 Cadillac CTS and are dealing with fuel delivery issues, here is the short answer: The 2009 Cadillac CTS does not have a separate, standalone fuel pump control module located outside the fuel tank. Instead, the fuel pump control function is integrated into the vehicle’s main computer system. The fuel pump itself is located inside the fuel tank, and the fuel pump relay is located in the rear compartment fuse block. The power to the fuel pump is controlled by the Powertrain Control Module (PCM) through the fuel pump relay, not by a separate control module.

Understanding the Fuel Pump System on the 2009 Cadillac CTS

The 2009 Cadillac CTS uses a modern electric fuel pump that is mounted inside the fuel tank. This is standard for most vehicles from that era. The fuel pump attaches to the fuel sender assembly inside the tank and supplies high-pressure fuel to the engine's fuel injection system. The PCM controls the operation of the fuel pump by sending a signal to the fuel pump relay. When you turn the key to the "on" position, the PCM energizes the relay, which then sends power to the fuel pump.

Where the Fuel Pump Is Physically Located

The fuel pump is inside the fuel tank. The fuel tank on the 2009 Cadillac CTS is located under the rear of the vehicle, behind the rear axle. To access the fuel pump, you typically need to either drop the fuel tank or, in some cases, access it through an interior panel. On many 2009 vehicles, the pump is accessed through a round or square panel located under the rear seat cushion or in the trunk floor area. However, for the Cadillac CTS, many owners report that the fuel tank must be removed (dropped) to access the pump.

Where the Fuel Pump Relay Is Located

The fuel pump relay is located in the rear compartment fuse block. This fuse block is typically found in the trunk area, often on the left or right side behind a trim panel. According to the fuse box diagram for the 2009 Cadillac CTS, the rear compartment fuse block contains the "FUEL/PUMP RLY" (fuel pump relay) and a "FUEL/PUMP" mini 20A fuse. If you are having trouble with the fuel pump not getting power, checking this relay and fuse should be your first step.

Common Symptoms of a Failing Fuel Pump or Electrical Issue

If you suspect your fuel pump is not working, here are the most common symptoms to watch for:

  1. Engine cranks but will not start: This is the most obvious sign. If the fuel pump is not delivering fuel, the engine will crank but never fire up.
  2. Engine sputters at high speeds: A failing pump may struggle to maintain fuel pressure at higher RPMs, causing the engine to hesitate or sputter.
  3. Loss of power under stress: When going uphill or accelerating hard, a weak pump cannot provide enough fuel, leading to a noticeable loss of power.
  4. Whining noise from the fuel tank: A healthy fuel pump makes a quiet hum. If you hear a loud whining or buzzing sound coming from the rear of the car, the pump may be failing.
  5. Decreased gas mileage: A pump that is not working efficiently can cause the engine to run rich or lean, reducing fuel economy.

How to Diagnose the Problem

Before you assume the fuel pump is bad, it is important to go through a systematic diagnosis. Many times, the issue is not the pump itself but a related electrical component.

Step 1: Check the Fuel Pump Fuse and Relay
Start with the simplest checks. Open the rear compartment fuse block and locate the fuel pump fuse (20A MINI) and the fuel pump relay. Pull the fuse and inspect it. If the metal strip inside is broken, the fuse is blown. A blown fuse is often a symptom of a larger problem, not the root cause itself. Common causes of a blown fuel pump fuse include a short circuit in the wiring, a failing fuel pump drawing too much current, or a clogged fuel filter making the pump work harder. If the fuse looks good, swap the fuel pump relay with a similar relay in the fuse box (like the horn relay) to see if the pump starts working.

Step 2: Listen for the Fuel Pump Prime
Turn the ignition key to the "on" position (do not start the engine). Listen carefully from the rear of the vehicle. You should hear a brief humming or whirring sound for about 2-3 seconds. This is the fuel pump priming the system. If you do not hear anything, there is a good chance the pump is not receiving power, or the pump itself is dead.

Step 3: Check for Power at the Fuel Pump
If you have a multimeter, you can check for voltage at the fuel pump connector. This requires accessing the fuel pump (usually by removing the rear seat or dropping the tank). With the key in the "on" position, you should see battery voltage (around 12 volts) at the pump connector for a few seconds. If you have power but the pump does not run, the pump is faulty. If you have no power, the issue is likely in the relay, fuse, wiring, or the PCM.

Step 4: Check the Fuel Pressure
The most definitive way to check the fuel pump is to test the fuel pressure. A mechanic can attach a fuel pressure gauge to the service port on the fuel rail. The 2009 Cadillac CTS with a 3.6L engine uses a direct injection system that operates at very high pressures. The low-pressure side (from the in-tank pump) typically runs at around 50-60 psi, while the high-pressure side (from the engine-driven pump) can reach up to 12,000 kPa (about 1,740 psi). If the low-pressure fuel pump is failing, the pressure reading will be below the manufacturer's specification.

What Else Could Be Wrong?

Do not assume a bad fuel pump is the only possibility. Several other components can cause similar symptoms.

  • Defective Fuel Pump Relay: The relay is a common failure point. If the relay is bad, the pump will not receive power even if everything else is fine.
  • Clogged Fuel Filter: A severely clogged fuel filter can restrict fuel flow, making the pump work harder and eventually fail. It can also mimic the symptoms of a bad pump.
  • Activated Inertia Switch (Impact Sensor): Some vehicles have an inertia switch that cuts power to the fuel pump in the event of a collision. If this switch is accidentally triggered (e.g., by hitting a pothole or a bump), the pump will not run. Check your owner's manual for the location of this switch.
  • PCM (Engine Control Unit) Issues: The PCM controls the fuel pump relay. A problem with the PCM or a sensor that feeds it information can prevent the pump from operating.
  • Wiring Problems: Damaged, corroded, or frayed wires in the fuel pump circuit can cause intermittent or complete failure. This is especially common in older vehicles exposed to road salt and moisture.

Why Choose a KEMSO Fuel Pump for Your 2009 Cadillac CTS

If you have diagnosed the problem and confirmed that the in-tank fuel pump needs to be replaced, you want a part that is reliable, affordable, and backed by a solid warranty. This is where KEMSO Fuel Pumps stand out from the competition.

KEMSO fuel pumps are built as high-performance, OEM replacement units. This means they are engineered to match the exact specifications of your vehicle's original pump, including fuel pressure, flow rate, and electrical characteristics. You get the same performance and reliability as a dealer part, but at a much more reasonable price.

Every KEMSO fuel pump comes with a lifetime warranty. This is not a limited one-year warranty; it is a lifetime guarantee that covers defects in materials and workmanship for as long as you own the pump. If it ever fails due to a manufacturing defect, KEMSO replaces it for free. This level of confidence is rare in the aftermarket parts industry and gives you true peace of mind.

KEMSO pumps are designed for a direct bolt-in installation. You do not need to modify any wiring, brackets, or fuel lines. Whether you are a DIY mechanic or having a professional install it, the process is straightforward.

Visit KEMSO Racing today to find the exact fuel pump for your 2009 Cadillac CTS and take advantage of their lifetime warranty:
https://www.kemsoracing.com/

Final Thoughts

In summary, the 2009 Cadillac CTS fuel pump is located inside the fuel tank, accessible by dropping the tank. There is no separate fuel pump control module outside of the tank; the PCM controls the pump through the relay. When troubleshooting a no-start or fuel delivery issue, always start by checking the fuel pump fuse and relay in the rear compartment fuse box. If those are fine, move on to listening for the pump prime and checking for power at the pump. Do not forget to consider other potential causes like a clogged filter, a faulty relay, or a triggered inertia switch.

If you do end up needing a replacement fuel pump, choose a part that offers reliability and value. KEMSO fuel pumps provide OEM-quality performance with the added security of a lifetime warranty. For more information or to find the right pump for your Cadillac, visit https://www.kemsoracing.com/ today.


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