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.
Overview - Cold Start Fuel Reservoir And Fuel Injector: Notes
The cold start fuel system supplies gasoline to the engine during low ambient temperatures, to enable vehicles with a high percentage ethanol fuel to start the engine. The gasoline is in a small cold start fuel reservoir in the engine compartment.
The cold start fuel pump and the cold start valve are mounted to the cold start fuel reservoir. The cold start fuel pump and the cold start valve are connected in series with the cold start fuel line that connects to the intake manifold. The cold start fuel pump voltage is supplied from the cold start relay controlled by the PCM.
During a low ambient temperature cold start, the PCM grounds the cold start relay control circuit, supplying voltage to the cold start fuel pump. The PCM commands the cold start valve solenoid on by grounding the cold start valve control circuit. The cold start valve allows the gasoline from the cold start fuel pump and reservoir to flow to the intake manifold, enabling additional fuel to start the engine during cranking. If the ambient temperature is below a calibrated threshold, the PCM will continue to supply gasoline from the cold start system for a calibrated time, until the engine idle stabilizes.
The PCM monitors the voltage circuit from the cold start relay to the cold start fuel pump for an open or short circuit conditions. The PCM will set a DTC if the expected voltage value is out of range for the commanded state.
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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.