P1237 - FAULT CODE - OBD2

P1237 FORD, LINCOLN, MERCURY: FUEL PUMP SECONDARY CIRCUIT FAULT

The fuel pump is an essential component of the engine combustion system. This device, located in the fuel tank, is designed to transport the necessary amount of fuel from the fuel tank to the engine at the proper pressure.

Older vehicles had mechanical pumps, which are driven by the camshaft or distributor shaft. More modern models of vehicles with fuel injection systems include electric pumps. These pumps deliver fuel to the injectors at a defined pressure.

The FPDM (Fuel Pump Driver Module) controls the voltage of the fuel pump, in order to maintain the pressure within the appropriate levels for proper engine performance. If this module detects a fault in the secondary circuit of the fuel pump, it will communicate it to the Powertrain Control Module (PCM), which will store the fault code P1237 OBD2.

• Check Engine lamp comes on.
• The engine does not start or has difficulty starting.
• The engine stops unexpectedly.

P1237 OBDII diagnostic code is set for one of the following reasons:

• The Fuel Pump Driver Module wiring may be faulty.
• The Fuel Pump Driver Module may be faulty.
• The fuel pump could be damaged.

To troubleshoot DTC P1237 OBD2 consider the following:

• Consult the Technical Service Bulletins.
• Inspect the Fuel Pump Controller Module wiring harnesses and check them for common damage such as burns or corrosion. If such conditions are discovered, make corrections as necessary.
• Check the FPDM circuit electrical connections for damage. Measure the voltages of this circuit and compare the results with the manufacturer's specifications. Repair if you discover insufficient voltages.
• Following the manufacturer's diagnostic steps, check the integrity of the FPDM and fuel pump. If you determine that these components are deficient in these tests, make the appropriate corrections.