Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC 56, Injection Pump Calibration Resistor Error: Notes
PCM uses a calibrated resistor mounted internally in injection pump to determine fuel rates. Resistor value is stored in PCM memory. If PCM memory has been disturbed or PCM has been replaced, PCM will relearn resistor value on next ignition cycle. DTC 56 will set when PCM has lost its memory and is unable to read a resistor value on the next ignition cycle. Possible poor performance problem. PCM will light MIL and a current and history DTC 56 will set. PCM will default to the lowest fuel table.
- This step determines if a problem exists with fuel solenoid driver connection or if injection pump is faulty.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.