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.
Circuit Description
The Powertrain Control Module (PCM) uses information from the Intake Air Temperature (IAT) and the Engine Coolant Temperature (ECT) sensors to determine ambient temperature at cold start-up. Alcohol content, alcohol percentage, information is supplied to the PCM from the Fuel Composition Sensor (FCS). When the alcohol content is too high for a given ambient temperature an internal DTC will set in the PCM. This code is for information only, in order to aid the technician for symptom related complaints such as hard starting in cold ambient temperatures due to fuel blends which are not recommended for the ambient temperature. In some cases the DTC may set if there is contamination present in the fuel causing the calculated alcohol content to be higher than expected.
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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.