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Q501 4 Cylinder MT Application
DTC Troubleshooting Data
Version: 0.1
Date: 21-Sep-2018
Prepared By: Mithi Prasad, Sarang Kulkarni, Manish Gupta
Checked By: Yogesh Jadhav
Approved By: Satish Kumar P
Page: 714 of 1052
Copyright ©
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.
P0127-4B: Intake Air Temperature Too High – EGR high pressure intake air manifold overheating
Overview:
DTC Description (User Friendly)
EGR high pressure intake air manifold overheating
ECU Pin Number
A067, A088, A040, A079, A078
Customer Symptom
MIL ON1, Hesitation or surge at idle or upon light acceleration,
Reduction in Fuel efficiency
Fault Effects (On Vehicle)
Slight reduction in fuel efficiency
Lamp Status (If Any)
MIL ON
Fault Detection Condition (Root cause)
The fault is set if the closure of the EGR valve is not sufficient to
reduce the intake manifold air temperature within time 22 sec, or if
EGR valve is already closed for time 22 sec.
The hysteresis with upper threshold 130 sec is introduced in order to
avoid the exceptional case of toggling of the de-bouncing of the error
path.
Normal Operating Condition
No Fault
Probable Trouble Area
1.Low intercooler efficiency
2. EGR valve leaking into intake manifold
3. Engine overheat
Healing Condition
Rectify the error
Clear through diagnostic tool
Ignition OFF & ON
Component / Function Details:
EGR works by recirculating a portion of an engine's
exhaust gas
back to the engine
cylinders
. This dilutes the O2 in the
incoming air stream and provides gases inert to combustion to act as absorbents of combustion heat to reduce peak
incylinder temperatures. NOx is produced in a narrow band of high cylinder temperatures and pressures.
EGR valve controls the amount of exhaust airflow to be re-circulated into the engine cylinders.
Preliminary Checks:
1. Check whether the customer voice / view about the issue is matching with the fault effects mentioned in above
Table. If yes, go ahead with next steps. If not, check for other DTC’s presence.
2. Check whether other customers report similar complaints earlier. If yes, perform the preliminary checks with
respect to earlier issue closure.
3. Check for wiring harness dis-continuity between the mass air flow Sensor and EMS ECU.
4. Check for wiring harness dis-conintuity between HP EGR valve and EMS ECU
5. Check whether any faults related to MAF sensor are also present, rectify them by following their rectification
procedure.
6. Check for damage of pins at ECU connector.
7. Check whether the EGR valve is leaking into intake manifold
8. Check whether the intercooler is operating fine (with its specified efficiency)
9. Check if Engine overheat is observed. If so check whether coolant level is low or any cooling fan issues.
Trouble Shooting: