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OSPREY- Application
DTC Troubleshooting Data
Version: 4.0
Date: 10-02-2017
Prepared by: Mithipati Prasad
Checked by: G S Raju / Senthilnathan S
Page: 240 of 654
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TATA MOTORS Ltd.
This document must not be used in any way, such as copying and redistributing to third parties, without the consent of author.
P0400: Exhaust Gas recirculation Flow Air Error – Too Low or Too High
Overview:
DTC Description as per ISO standard
EGR “A” Flow
ECU Pin Number
45
Customer Symptom
Loss of power
Black smoke
Fault Effects (On Vehicle)
EGR is disabled
Black Smoke
Loss of Power
Lamp Status (If Any)
MIL is ON
Fault Detection Condition
This DTC gets logged if the
1. EGR air error is more than the min/ max value.
2. Damaged hose connecting EGR - EVR to EGR valve
Normal Operating Condition
No Faults related to EGR air flow error.
Probable Trouble Area
EGR Valve, EGR Modulator, Vacuum pump, Air filter clogged, Intake
Air circuit clog, ECU Grounding points, Air mass flow sensor,
Atmospheric pressure sensor, Wiring harness
Healing Condition
Clear the errors, Ignition OFF to ON, engine idle & fly-up condition
Component Details:
An incomplete burnt gas in exhaust is return to the cylinder. EGR works by recalculating a portion of an engine's exhaust
gas back to the engine cylinder. Intermixing the incoming air with recalculated exhaust gas dilutes the mix with inert gas
and in turn reduce the combustion temperatures for reducing NOx emissions.
Preliminary Checks
x
Check whether the customer voice / view about the issue is matching with the fault effects mentioned above. If
yes, go ahead with next steps. If not, check for other DTC’s presence.
x
Check whether similar complaints are earlier reported. If yes, perform the preliminary checks with respect to
earlier issue closure.
x
Check whether the EMS ECU is getting power supply and GND. Rectify wiring Harness as per the schematic if
found faulty. Check EGR /AMF sensor/Vacuum pump functionality
x
Check whether the EGR Valve / EGR Modulator / Vacuum pump are mechanically damaged
x
Check whether the Inlet air circuit is clogged
x
Check whether the air filter is clogged
x
Check whether the Air mass flow sensor is physically damaged
x
Check whether the atmospheric pressure sensor mounted on ECU is physically damaged.
x
Check whether the vacuum hose connections are not damaged / open.