P0401
Read the instructions below then
start the fault diagnostic procedure.
Symptom: CHECK ENGINE.
EGR Flow To Low
Fault symptoms
On-Board Diagnostics
Type of diagnosis:
Enable criteria:
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Battery voltage should be 10.2-15.8 V.
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P1636 or P1637 should not be detected.
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Rpm changes between two measurements should not exceed a difference of 40 rpm.
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The difference between two injections should not exceed 1.5 mm
3
/C.
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Gear in neutral position.
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Requested EGR flow should be 26-65%.
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Speed should be 0-10 km/h.
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Injection quantity should be 3-9 mm
3
/C.
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Intake air temperature should be 20-95 °C.
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Atmospheric pressure should be 90-110 kPa.
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These conditions should be fulfilled for 3 seconds before diagnostics run.
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Fault criteria:
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EGR flow is 21% lower than desired.
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Dependents:
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P0101, P0102, 0103, P0112, P0113.
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System reaction to a fault:
OK report:
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Fault criteria not fulfilled.
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Fault handling:
(See section
Fault handling III, other emissions-related components and functions
for more information)
Diagnostic help
Read value:
Target EGR Ratio,
EGR Ratio
The EGR function is switched off after 1 minute of idling (EGR valve closed). As soon as the accelerator pedal is touched, EGR control is reactivated.
See also description of read value under
"Read Values" menu
for more information.
Checking the wiring
Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.
