What Does P1238 Mean?
DTC P1238 indicates a general malfunction in the fuel pump secondary circuit. The PCM or fuel pump driver module has detected an electrical fault in the circuit that provides power directly to the fuel pump motor. This can encompass open circuits, intermittent connections, or voltage irregularities that prevent reliable fuel pump operation.
Common Causes
30%
Fuel pump driver module secondary output circuit failure
25%
Intermittent wiring connection in the fuel pump secondary circuit
20%
Fuel pump motor beginning to fail with erratic current draw
15%
Corroded fuel pump connector at the tank sending unit
10%
Fuel pump inertia switch partially tripped or high resistance
Diagnostic Steps
1
Check the fuel pump inertia switch (if equipped) — reset it and verify low resistance across its contacts.
2
Monitor fuel pump secondary circuit voltage and current at the FPDM while commanding various pump speeds.
3
Perform a thorough inspection of the fuel pump wiring from the FPDM to the tank connector, looking for chafing, corrosion, or rodent damage.
4
Load-test the fuel pump by measuring current draw while the pump is running — erratic or spiking current indicates internal pump failure.
5
Check for updated FPDM calibration or hardware revision from the manufacturer via TSB lookup.
Estimated Repair Cost
$150 - $700
Parts + labor, varies by vehicle and location
DTC P1238 indicates a general malfunction in the fuel pump secondary circuit. The PCM or fuel pump driver module has detected an electrical fault in the circuit that provides power directly to the fuel pump motor. This can encompass open circuits, intermittent connections, or voltage irregularities ...
The most common cause of P1238 (Fuel Pump Secondary Circuit Malfunction) is: Fuel pump driver module secondary output circuit failure
Typical repair costs for P1238 range from $150 to $700, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A secondary circuit malfunction can cause intermittent fuel delivery interruptions. This may manifest as random stalling, hesitation, or difficulty restarting, all of which pose safety risks during normal driving.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1238 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel Delivery
Difficulty
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