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
PCM monitors EGR valve pintle position input to ensure that valve responds properly to commands from PCM. PCM compares actual EGR position with desired EGR position when valve is commanded open. If actual EGR position is 15 percent less than desired EGR position when PCM is commanding EGR valve opened, DTC will set.
DTC P0404 will set when no ECT, HO2S, IAT, MAF or TP sensor DTCs are set, TP sensor angle is greater than 2 percent, DTC P040 diagnostic not running, or system voltage is greater than 10 volts.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.
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