P0627 on 2004-2009 Cadillac SRX 3.6L: Fuel Pump Control Circuit Causes and Fixes

What's Unique About the 2004-2009 Cadillac SRX

Unlike many contemporary vehicles that use a separate, and often problematic, Fuel Pump Driver Module (FPDM), the first-generation Cadillac SRX uses a simpler and more traditional fuel pump relay system. The Engine Control Module (ECM) directly commands the fuel pump relay located in the underhood fuse box. This makes diagnosis more straightforward, as you are primarily dealing with a relay, its wiring, the fuse, and the fuel pump itself, rather than a complex electronic module.

Symptoms You May Notice

• Engine cranks but will not start
• Engine stalls intermittently, especially while driving
• Engine may start briefly then shut down.
• Hesitation or loss of power during acceleration
• Illuminated Check Engine Light.

Most Likely Causes

1. Faulty Fuel Pump Relay 🔴 High Probability Relays are electromechanical switches that can wear out over time. Due to its low cost and ease of access in the underhood fuse box, it's the most logical first part to check and a very common failure point for this code.
   How to confirm: Locate the fuel pump relay in the underhood fuse box. You can swap it with an identical relay from a non-essential system (like the horn or A/C compressor) to see if the problem is resolved. If the car starts and runs properly with the swapped relay, the original relay is bad.
   Typical fix: Replace the fuel pump relay.
   Est. part cost: $10-$25
2. Failed In-Tank Fuel Pump Assembly 🟡 Medium Probability The electric motor in the fuel pump can wear out and fail, leading to an open circuit condition that triggers P0627.
   How to confirm: After confirming the relay and fuse are good, check for power and ground at the fuel pump connector when the key is turned to the 'ON' position. If power and ground are present but the pump does not run (no humming sound from the tank), the pump has failed.
   Typical fix: Replace the entire fuel pump module assembly inside the fuel tank. This requires dropping the fuel tank for access.
   Est. part cost: $150-$400
3. Damaged Wiring or Connectors ⚪ Low Probability Wires can become corroded, chafed, or broken over time, especially the harness near the fuel tank or the connector on top of the fuel pump module. High resistance from corrosion is a common cause.
   How to confirm: Visually inspect the wiring harness from the ECM to the fuel pump relay, and from the relay to the fuel pump. Pay close attention to the connector on the fuel pump assembly for signs of melting or corrosion. Perform a continuity test on the control circuit wire (from ECM to relay) and the power wire (from relay to pump) if a visual fault isn't found.
   Typical fix: Repair or replace the damaged section of the wiring harness and any corroded or melted connectors.
   Est. part cost: $5-$100
4. Blown Fuel Pump Fuse ⚪ Low Probability A failing fuel pump can draw excessive current, causing the fuse to blow as a protective measure. A short circuit in the power wire to the pump will also cause this.
   How to confirm: Locate the fuel pump fuse in the underhood fuse box and visually inspect it. Test with a multimeter for continuity. A blown fuse often indicates an underlying problem, such as a failing pump or a short circuit.
   Typical fix: Replace the fuse. If it blows again, further diagnosis of the circuit and pump is required.
   Est. part cost: $1-$5

Rare But Worth Checking

• Failed Engine Control Module (ECM): This is extremely rare. The ECM should only be considered after all other possibilities, including all wiring, the relay, and the fuel pump itself, have been definitively ruled out.

Diagnosis Steps

1. Retrieve all stored DTCs with an OBD-II scanner to confirm P0627 is the primary code.
2. Locate the underhood fuse box. Inspect the fuse labeled 'FUEL PUMP'. If it's blown, replace it and see if it blows again. If it does, suspect a short circuit or a failing pump drawing too much current.
3. If the fuse is good, locate the 'FUEL PUMP' relay. Swap this relay with an identical one from a different circuit (e.g., horn or A/C compressor). If the vehicle now starts, the original relay is faulty and must be replaced. This is the most common fix.
4. If the relay swap does not fix the issue, listen for the fuel pump to prime for 2-3 seconds when the ignition is first turned to 'ON'. If there is no sound from the fuel tank area, the pump is not activating.
5. If the pump does not prime, access the fuel pump electrical connector on top of the fuel tank. Using a multimeter, check for 12V power at the power wire for the first few seconds after the key is turned on. If power is present but the pump doesn't run, the fuel pump has failed.
6. While at the connector, inspect it carefully for any signs of heat damage, melting, or corrosion on the pins and wires. A bad connection here is a known failure point.
7. If there is no power at the fuel pump connector, check for an open or short in the wiring between the fuel pump relay socket and the fuel pump.
8. Check the control circuit for the relay. The ECM sends a ground signal to activate the relay. Verify the integrity of this wire between the ECM and the relay socket.
9. If all wiring, the fuse, the relay, and the pump are confirmed to be good, the issue may be with the ECM's driver circuit, though this is highly unlikely.

Parts You'll Likely Need

• Fuel Pump Relay (OEM #13500113) — This is the most common failure point for a P0627 code on this vehicle and the easiest/cheapest to replace. It is a multi-purpose relay used in other locations as well.
  Trusted brands: ACDelco, Standard Motor Products (SMP)
  OEM price range: $15-$30
  Aftermarket price range: $10-$25
• Fuel Pump Module Assembly (OEM #19417963) — If the relay and wiring are good, the fuel pump itself is the next likely culprit. The assembly includes the pump, strainer, and fuel level sending unit.
  Trusted brands: ACDelco, Delphi, Spectra Premium
  OEM price range: $300-$450
  Aftermarket price range: $150-$300

Mechanic-Grade Diagnostic Values

• Fuel Pump Relay Control Circuit Voltage (feedback to ECM) — expected: The ECM provides ignition voltage to the relay coil and monitors a feedback circuit that is pulled up to 2.5 volts internally.. Failure: The ECM sets P0627 if it detects the voltage on the control circuit is within a predetermined (unexpected) range when the relay is commanded OFF.
• Voltage at Fuel Pump Connector — expected: Approximately 12V for the first 2-3 seconds after the ignition is turned to 'ON' (during prime).. Failure: 0V or significantly less than 12V indicates a problem upstream (relay, wiring, fuse).
• Fuel Pressure (at fuel rail test port) — expected: Approximately 58-62 PSI on the similar 3.6L V8 platform, which should be close for the V6.. Failure: Pressure below specification indicates a weak pump, clogged filter, or leak. No pressure indicates the pump is not running at all.

Scan Tool Commands That Help

• Tech2 / GDS2: Fuel Pump Relay ON/OFF Command — This bidirectional control allows a technician to command the fuel pump relay ON and OFF directly from the scan tool. It's used to verify if the relay clicks, if the pump runs, and to check for voltage at the pump connector without needing to crank the engine, isolating the control side from the load side of the circuit.
• Tech2 / GDS2: Fuel Injector Balance Test — While not a direct test for P0627, this function can help evaluate the health of the entire fuel delivery system. It measures the pressure drop as each injector fires, which can indirectly indicate if the fuel pump is capable of maintaining adequate pressure under load.

Wiring & Ground Locations

• G401 / G402 — G401 is located at the rear of the right rear shock tower on the D-pillar. G402 is in the same location on the left side.. The fuel pump and sender assembly is grounded through one of these points. A corroded or loose ground at G401 or G402 can cause an open circuit or high resistance, preventing the fuel pump from running and potentially triggering a P0627 or other fuel-related codes.
• Fuel Pump Connector — On top of the fuel tank, accessible by either dropping the tank or, in some cases, through an access panel under the rear seat.. This connector is a common failure point. Due to its location, it is susceptible to moisture and corrosion, which can lead to high resistance, melting, and an open circuit, directly causing code P0627.
• Underhood Fuse Block — In the engine compartment, on the driver's side.. This block contains both the fuel pump fuse and the fuel pump relay. It is the primary diagnostic starting point for any power-related issues in the fuel pump circuit.

Real Owner Repair Stories

• YouTube channel 'Jon Will Fix It' (2013 Cadillac SRX 3.6L (Note: 2nd Gen, but diagnostic process for pump/wiring is similar)) — Crank no start.
  ❌ Tried (didn't work) Initial scan showed multiple codes, including P0232 (Fuel Pump Control Circuit High) and P023F (Fuel Pump Secondary Circuit/Open).
  ✅ What actually fixed it After verifying the fuse was good, a bidirectional scan tool test was used to command the fuel pump on. No sound was heard from the pump. Testing at the fuel pump connector (X46) showed power was being sent, but the pump was not activating. The final fix was replacing the in-tank fuel pump assembly.
• YouTube channel 'P0627 Fix For Fuel Pump Open Circuit' (2015 Lincoln MKS (Note: Different vehicle, but demonstrates a common wiring failure mode for P0627)) — Check Engine Light with code P0627.
  ❌ Tried (didn't work) Checked fuel pump fuse, which was good.
  ✅ What actually fixed it The technician found a poorly repaired wire at the fuel pump module connector. The wire was exposed and making intermittent contact. The final fix was to properly de-pin the connector, re-crimp the wire to the terminal, and insulate it with heat shrink, resolving the open circuit.

OEM Part Supersession History

• 19116059, 19116962, 88988889 → 13500113 — Part consolidation and design updates by GM over time.
  Heads up: The newer part number 13500113 is the correct and current replacement for the older numbers and is fully compatible.
• 20838810, 20838811 → N/A - These are harness numbers — These are part numbers for the fuel tank wiring harness assembly.
  Heads up: If replacing the harness pigtail at the pump, ensure you get the correct one as there are different parts for different model years within the generation.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Premature Timing Chain Stretch 🔴 High — Common between 60,000 and 120,000 miles. Exacerbated by extended oil change intervals. (Ref: Special Coverage Adjustment #11340 / TSB 12-06-01-009D covered replacement for 10 years/120k miles.)
• Clogged or Disconnected Sunroof Drains 🟠 Medium — Very common issue where front drain tubes shrink, pull out of the firewall, or clog, causing water to leak into the passenger or driver footwell.
• Front Wheel Bearing Failure 🟠 Medium — Frequently reported failure, causing a roaring or humming noise that changes with turning.
• Failed Driveshaft Center Support Bearing 🟠 Medium — The rubber in the carrier bearing deteriorates, causing a clunking noise or vibration while driving. Often requires replacement of the entire driveshaft.
• Ignition Switch Failure (Recall) 🔴 High — A recall was issued because weight on the key ring could cause the ignition switch to move out of the 'Run' position, shutting off the engine while driving. (Ref: NHTSA Recall 14V346000)

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: For this repair, a used part is generally not recommended for the fuel pump itself due to the high labor cost of replacement. However, obtaining a used wiring harness connector pigtail from a junkyard vehicle can be a cost-effective solution if only the connector is damaged and the donor vehicle's connector is in excellent condition.

Donor-vehicle mileage cap: roughly under 80000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For a connector pigtail: Inspect for any signs of melting, charring, or discoloration on the plastic.
• Check the pins for corrosion (green or white powder) or signs of water intrusion.
• Ensure the wire insulation is not brittle, cracked, or frayed.
• Confirm the locking tabs on the connector are intact and not broken.

OEM-only on this vehicle (don't cheap out):

• Fuel Pump Relay: While aftermarket relays exist, the cost difference is minimal, and the ACDelco OEM relay (PN 13500113) is a proven, reliable part.

Aftermarket brands forum-validated for this vehicle:

• Delphi: Delphi is a major OEM supplier to GM and their fuel pumps are generally considered to be of equivalent quality to ACDelco.
• Spectra Premium: Often cited as a reliable aftermarket alternative for fuel pump assemblies.

Brands owners have reported issues with on this vehicle:

• No-name or unbranded 'white box' fuel pump assemblies from online marketplaces. These often have high failure rates and may not meet OEM specifications for pressure and flow, leading to repeat repairs.

Related OBD-II Codes

• P0628 — A direct companion code indicating 'Fuel Pump 'A' Control Circuit Low'. It points to a different fault (a short to ground) in the exact same circuit that P0627 monitors for an open.
• P0629 — A direct companion code indicating 'Fuel Pump 'A' Control Circuit High'. It points to a short to power within the same fuel pump control circuit where P0627 indicates an open.
• P0231 — Indicates 'Fuel Pump Secondary Circuit Low'. While P0627 is for the control circuit (ECM to relay), this code relates to the power circuit (relay to pump). A major wiring issue or failed pump could potentially affect both circuits.
• P0087 — Indicates 'Fuel Rail/System Pressure - Too Low'. This is a direct and expected consequence of the condition causing P0627, as an open fuel pump control circuit prevents the pump from running and building pressure.
• P0606 — Indicates 'ECM/PCM Processor Fault'. The article mentions that a faulty ECM driver circuit is a highly unlikely but possible cause for P0627. A failing ECM can trigger internal processor fault codes like this one.

Frequently Asked Questions