P1237: Fuel Pump Secondary Circuit Malfunction

Definition

The OBD2 code P1237 indicates a malfunction in the secondary circuit of the fuel pump, which may involve issues with the fuel pump relay, wiring, or the fuel pump itself, affecting fuel delivery to the engine

Common causes

Faulty fuel pump
Damaged wiring or connectors
Failed fuel pump relay
Blown fuse
Poor ground connection
Malfunctioning fuel pump control module
Short circuit in the fuel pump circuit
Open circuit in the fuel pump circuit

Common misdiagnoses

Fuel pump failure
Fuel filter blockage
Fuel pressure regulator issues
Wiring or connector problems
Engine control module (ECM) failure
Relay issues
Injector problems
Ignition system faults

Troubleshooting steps

1. Check for Additional Codes

Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context and help identify related issues
2. Inspect the Fuel Pump Relay
3. Locate the fuel pump relay in the fuse box
4. Check for any signs of damage or corrosion
5. Test the relay using a multimeter to ensure it is functioning properly. If faulty, replace it
6. Examine the Fuel Pump Fuse
7. Check the fuse associated with the fuel pump circuit
8. Replace any blown fuses and check if the code returns
9. Inspect Wiring and Connectors
10. Visually inspect the wiring and connectors leading to the fuel pump for any signs of damage, corrosion, or loose connections
11. Repair or replace any damaged wiring or connectors
12. Test the Fuel Pump
13. Use a multimeter to check the voltage at the fuel pump connector while the ignition is in the "ON" position (but the engine is not running)
14. If there is no voltage, the issue may be upstream in the circuit (relay, fuse, or wiring)
15. Check the Fuel Pump Ground
16. Ensure that the ground connection for the fuel pump is secure and free of corrosion
17. Test the ground with a multimeter to ensure it has a good connection
18. Perform a Fuel Pressure Test
19. Use a fuel pressure gauge to check if the fuel pump is delivering the correct pressure
20. If the pressure is low, the fuel pump may be failing and may need to be replaced
21. Inspect the Fuel Pump Control Module
22. If your vehicle has a fuel pump control module, check for any faults or issues with it
23. Test the module according to the manufacturer's specifications
24. Check for Short Circuits
25. Inspect the wiring for any signs of short circuits or grounding issues that could affect the fuel pump circuit
26. Clear the Code and Test Drive
27. After performing repairs, clear the trouble codes using the OBD-II scanner
28. Take the vehicle for a test drive to see if the code returns. 1
29. Consult a Professional
30. If the issue persists after performing these steps, it may be necessary to consult a professional mechanic for further diagnosis. Always refer to the vehicle's service manual for specific procedures and specifications related to your make and model

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Check for Additional Codes

2. Inspect the Fuel Pump Relay

3. Locate the fuel pump relay in the fuse box

4. Check for any signs of damage or corrosion

5. Test the relay using a multimeter to ensure it is functioning properly. If faulty, replace it

6. Examine the Fuel Pump Fuse

7. Check the fuse associated with the fuel pump circuit

8. Replace any blown fuses and check if the code returns

9. Inspect Wiring and Connectors

10. Visually inspect the wiring and connectors leading to the fuel pump for any signs of damage, corrosion, or loose connections

11. Repair or replace any damaged wiring or connectors

12. Test the Fuel Pump

13. Use a multimeter to check the voltage at the fuel pump connector while the ignition is in the "ON" position (but the engine is not running)

14. If there is no voltage, the issue may be upstream in the circuit (relay, fuse, or wiring)

15. Check the Fuel Pump Ground

16. Ensure that the ground connection for the fuel pump is secure and free of corrosion

17. Test the ground with a multimeter to ensure it has a good connection

18. Perform a Fuel Pressure Test

19. Use a fuel pressure gauge to check if the fuel pump is delivering the correct pressure

20. If the pressure is low, the fuel pump may be failing and may need to be replaced

21. Inspect the Fuel Pump Control Module

22. If your vehicle has a fuel pump control module, check for any faults or issues with it

23. Test the module according to the manufacturer's specifications

24. Check for Short Circuits

25. Inspect the wiring for any signs of short circuits or grounding issues that could affect the fuel pump circuit

26. Clear the Code and Test Drive

27. After performing repairs, clear the trouble codes using the OBD-II scanner

28. Take the vehicle for a test drive to see if the code returns. 1

29. Consult a Professional

30. If the issue persists after performing these steps, it may be necessary to consult a professional mechanic for further diagnosis. Always refer to the vehicle's service manual for specific procedures and specifications related to your make and model