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.
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HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 58 (ENGINE CONTROLS SELF-DIAGNOSTICS - 4.3L)DIAGNOSTIC TESTSDTC P0404: EGR VALVE OPEN PINTLE POSITIONCONDITIONS FOR RUNNING DTC
1999 GMC Forward Control 5.7 R, Automatic
Conditions For Running DTC
1999 GMC Forward Control 5.7 R, AutomaticSECTION Conditions For Running DTC
WARNING: This page is about a different car, the 2002 GMC Savana and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
- The ignition voltage is more than 11.7 volts.
- The commanded EGR position is more than 0 percent.
- The EGR flow test is not active.
- The Desired EGR does not change more than 20 percent.
RENDER: 1.0x
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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.