P0627: Fuel Pump ""A"" Control Circuit Open

Definition

The OBD2 code P0627 indicates that there is an open circuit in the fuel pump "A" control circuit, which means the engine control module (ECM) is not receiving the expected signal from the fuel pump circuit, potentially leading to fuel delivery issues

Common causes

Open circuit in the fuel pump control wiring
Faulty fuel pump relay
Defective fuel pump
Bad ground connection
Malfunctioning engine control module (ECM)
Corroded or damaged connectors
Blown fuse in the fuel pump circuit

Common misdiagnoses

Fuel pump failure
Fuel pump relay issues
Wiring harness problems
Engine control module (ECM) failure
Fuel filter blockage
Ignition switch malfunction
Ground connection issues
Short circuit in the fuel pump circuit
Faulty fuel pressure regulator
Injector problems

Troubleshooting steps

1.Check the Code
Use an OBD-II scanner to confirm that the P0627 code is present. Clear the code and see if it returns after a short drive
2.Inspect Wiring and Connectors
3.Visually inspect the wiring and connectors associated with the fuel pump control circuit. Look for any signs of damage, corrosion, or loose connections
4.Pay special attention to the wiring harness leading to the fuel pump relay and the fuel pump itself
5.Test the Fuel Pump Relay
6.Locate the fuel pump relay in the fuse box or relay panel
7.Swap it with a similar relay (if available) to see if the problem persists
8.If you have a multimeter, test the relay for continuity and proper operation
9.Check the Fuel Pump Fuse
10.Inspect the fuse related to the fuel pump circuit. If it is blown, replace it and see if the code returns
11.If the fuse blows again, there may be a short circuit in the wiring
12.Test the Fuel Pump
13.If the wiring and relay are in good condition, test the fuel pump itself. You can do this by applying direct power to the pump to see if it operates
14.If the pump does not work when powered directly, it may need to be replaced
15.Check the Power and Ground
16.Use a multimeter to check for voltage at the fuel pump connector while the ignition is in the "ON" position. You should see battery voltage
17.Also, check for a good ground connection at the fuel pump. A poor ground can cause the circuit to appear open
18.Inspect the PCM (Powertrain Control Module)
19.If all other components check out, the issue may lie with the PCM. Check for any software updates or known issues with the PCM for your vehicle make and model
20.In some cases, the PCM may need to be reprogrammed or replaced
21.Look for Additional Codes
22.Check for any other related trouble codes that may provide more context to the issue. Sometimes, multiple codes can point to a common problem
23.Consult Technical Service Bulletins (TSBs)
24.Look up any TSBs related to your vehicle's make and model that may address known issues with the fuel pump circuit
25.Professional Diagnosis
26.If you are unable to resolve the issue after these steps, consider seeking help from a professional mechanic who can perform more advanced diagnostics. By following these steps, you should be able to identify the cause of the P0627 code and take appropriate action to fix the issue

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1.Check the Code

2.Inspect Wiring and Connectors

3.Visually inspect the wiring and connectors associated with the fuel pump control circuit. Look for any signs of damage, corrosion, or loose connections

4.Pay special attention to the wiring harness leading to the fuel pump relay and the fuel pump itself

5.Test the Fuel Pump Relay

6.Locate the fuel pump relay in the fuse box or relay panel

7.Swap it with a similar relay (if available) to see if the problem persists

8.If you have a multimeter, test the relay for continuity and proper operation

9.Check the Fuel Pump Fuse

10.Inspect the fuse related to the fuel pump circuit. If it is blown, replace it and see if the code returns

11.If the fuse blows again, there may be a short circuit in the wiring

12.Test the Fuel Pump

13.If the wiring and relay are in good condition, test the fuel pump itself. You can do this by applying direct power to the pump to see if it operates

14.If the pump does not work when powered directly, it may need to be replaced

15.Check the Power and Ground

16.Use a multimeter to check for voltage at the fuel pump connector while the ignition is in the "ON" position. You should see battery voltage

17.Also, check for a good ground connection at the fuel pump. A poor ground can cause the circuit to appear open

18.Inspect the PCM (Powertrain Control Module)

19.If all other components check out, the issue may lie with the PCM. Check for any software updates or known issues with the PCM for your vehicle make and model

20.In some cases, the PCM may need to be reprogrammed or replaced

21.Look for Additional Codes

22.Check for any other related trouble codes that may provide more context to the issue. Sometimes, multiple codes can point to a common problem

23.Consult Technical Service Bulletins (TSBs)

24.Look up any TSBs related to your vehicle's make and model that may address known issues with the fuel pump circuit

25.Professional Diagnosis

26.If you are unable to resolve the issue after these steps, consider seeking help from a professional mechanic who can perform more advanced diagnostics. By following these steps, you should be able to identify the cause of the P0627 code and take appropriate action to fix the issue