Code Definition

P1238 — Fuel Pump Secondary Circuit Malfunction

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Generic

About P1238

P1238 is a manufacturer-specific powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1238 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1238 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

On vehicles that use a fuel pump driver module (FPDM) to control fuel pump speed, the secondary circuit is the high current path between the driver module and the fuel pump, and the PCM commands the module with a pulse width modulated signal while monitoring a feedback line. DTC P1238 is set when the PCM or driver module detects an abnormal condition in this secondary fuel pump circuit, such as an open circuit, a short to ground, a short to power, or excessive resistance. Because this circuit carries the current that actually runs the pump, a fault here directly affects fuel delivery. When the...

Join TaT to view the complete code information and diagnostic details.

Quick Facts