The most likely cause of this problem is a clogged EGR valve or EGR flow passages. Before replacing any parts, try cleaning the EGR valve, tube, and passages with throttle body or carburetor cleaner. Also, check for damage or loose vacuum hoses to the EGR valve.
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How to Fix the DTC P0400 2001 Nissan Altima Sedan?
Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
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What is the Cost to Diagnose the Code?
Labor: 1.0
The cost to diagnose the P0400 2001 Nissan Altima Sedan code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.
When is the Code Detected?
Exhaust Gas Recirculation (EGR) flow control is not responding
What are Code Possible Symptoms?
Engine Light ON (or Service Engine Soon Warning Light)
Engine hesitation
What Does the P0400 2001 Nissan Altima Sedan Code Mean?
Early Exhaust Gas Recirculation (EGR) systems component s include and EGR Valve, and Engine Control Μodule (ECΜ) Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Μodulator. Depending on the engine and driving conditions, the ECΜ will control the EGR Solenoid, which will operate the EGR Vacuum Μodulator to regulate the opening and closing of the EGR Valve.
P0400 2001 Nissan Altima Sedan Code - Exhaust Gas Recirculation Function No/Low Flow Detected