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Mercedes P0402

Mercedes P04022020-08-09T07:22:21+00:00

OBD Codes

P0402

Description of the defect

EGR Flow Excessive Detected
The EGR system is monitored for undesired EGR flow during idle. The EGR monitor looks at the DPF EGR signal at idle and compares it to the stored signal measured during key ON and engine OFF. The test fails when the signal at idle is greater than at key ON engine OFF by a calibrated amount.
Possible causes

Possible causes
List of elements that might trigger the appearance of this code

  • EGR valve stuck open
  • Plugged EGR vacuum regulator solenoid vent
  • Plugged EGR tube
  • Slow responding D.P.F. EGR sensor
  • Damaged DPF EGR sensor
  • Improper vacuum hose connection
  • Plugged vacuum hoses
  • EGRVR circuit shorted to ground
  • Damaged EGR vacuum regulator solenoid
  • Damaged PCM

Diagnostic help

Some tricks to help us for the diagnosis of the failure

A DPFEGR PID reading that is greater at idle than during key ON and engine OFF by 0.5 volt or a rough engine idle, may indicate a hard fault.

The Carbon Cleaning ?

Prevents maintenance on engine problems

Preventive engine cleaning enables you to restore engine parts rather than replacing them, thereby saving vehicle owners on costly parts, such as a new turbocharger ($ 1.350 – 3.100), catalytic converter ($ 600 – 2.000), DPF ($ 600 – 2.000) or EGR valve ($ 370 – 500).

These problems result mainly from poor combustion, which stifles the engine.

So before replacing your engine parts, try Carbon Cleaning. A dirty engine as the result of carbon deposits is the new threat to vehicle performance.

Make your online diagnosis

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