As the fuel pump relay controls power to the fuel pump, any faults with it can cause issues with the fuel pump, which can cause drivability problems for the vehicle. The fuel pump relay is usually controlled by the ignition or Powertrain Control Module, and when switched on, will provide current to the fuel pump so that it may function. It is often found in the fuse box located in the engine bay and functions as the primary electronic switch that controls power to the fuel pump. Possible CausesĮrror Code P1237 can be caused by multiple problems.The fuel pump relay is an electronic component that is found on virtually all vehicles equipped with an internal combustion engine. In other vehicle makes, the engine may not start at all. The most common symptom and usually the only symptom for this error code is the activation of the Check Engine light and the registration of the error code. The PCM then sets the error code to the DTC and activate the Check Engine light to notify the driver of the problem. The FPDM indicates to the PCM (powertrain control module, also known as ECM or engine control module in other vehicles makes) through the FPM (fuel pump monitor) circuit to highlight the detected concern. Error Code P1237 takes place when the FPDM has determined a problem in the fuel pump secondary circuit. The FPDM or Fuel Pump Driver Modules control the voltage to the Fuel Pump to help keep proper fuel pressure throughout the operating range of the engine. Specifications on the definition, troubleshooting, and repairs, of course, vary from one make and model to another. This error code is a generic trouble, meaning it applies to all vehicles equipped with OBD-II system, especially vehicles made since 1996 up to present. This code happens when the fuel pump driver module has determined a problem in the fuel pump secondary circuit. Error Code P1237 is defined as Fuel Pump Secondary Circuit Fault.

Testing fuel pump driver module