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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: 143 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.
P0191: Rail Pressure Sensor Fault (At Key ON)
Overview:
DTC Description as per ISO standard
Rail Pressure sensor fault (at key on)
ECU Pin Number
40
Customer Symptom
Engine may / may not start.
Engine stops after few seconds.
Fault Effects (On Vehicle)
Reduced torque Mode activated. Pilot injection disabled.
EGR is deactivated. Injector balancing is disabled.
IMV operates without any trim correction.
High pressure Leak detection test is prevented.
IMV is fully open. Rail pressure demand value is limited to Calibratable
bar.
Rail pressure sensing is deactivated.
Disables the Rail pressure build measurement.
Rail pressure control fault detection is deactivated.
Lamp Status (If Any)
CE lamp is on
Fault Detection Condition
(Root cause)
This DTC gets logged due to out of range pressure value at the time of
ignition key is on.
Normal Operating Condition
Diagnostic tool display the Rail pressure signal status at vehicle running
condition
Probable Trouble Area
Rail pressure sensor, ECU, Wiring harness
Healing Condition
Clear the errors, Ignition OFF to ON, engine idle, fly-up and specially
vehicle running in different speed condition
Component Details:
Rail pressure sensor is a piezoelectric type one, which is used to measure the fuel pressure inside the Rail. It provides the
pressure in terms of voltage to the ECU. This rail possesses an under pressure supply of diesel fuel which is ready to be
used by the injectors. The drop of pressure in the rail is immediately signaled by the sensor to the engine control unit. This
is followed by the restoration of pressure in the pump. It is the engine control unit that controls the fuel supply of the rail
from a pump possessing very high pressure. This is done by using a valve for controlling the pressure of fuel.
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 adequate fuel is available in the tank. Check there is no air entry in to the low pressure fuel line.
x
Check ECU pins and connector, replace if found defective.
x
Check HP circuit; refer HP circuit check and rectification procedure.
x
Check LP circuit; refer LP circuit check and rectification procedure.