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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: 385 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.
P1254: Rail Pressure Feedback Less Than Demand
Overview:
DTC Description as per ISO standard
Rail pressure control error-Positive error
ECU Pin Number
40
Customer Symptom
Engine vibration / abnormal noise.
CE lamp is on.
Fault Effects (On Vehicle)
Cylinder balancing is disabled.
Reduced torque mode activated.
Lamp Status (If Any)
CE lamp is on.
Fault Detection Condition
This DTC gets logged if the Rail pressure error is above upper threshold.
Normal Operating Condition
Diagnostic tool display the Rail pressure signal status at vehicle running
condition
Probable Trouble Area
Rail pressure sensor, ECU, IMV, HP fuel Pump, LP fuel circuit, Rail
discharge valve, 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.
x
Check there is no air entry in to the low pressure fuel line.
x
Ensure fuel filter is not clogged.
x
Ensure there is no leakage in the high pressure fuel line.
x
Check & ensure rail pressure sensor, IMV & EMS ecu connectors for proper fitment
x
Check for IMV related faults (P0251, P0253, P0255) and if found refer rectification process for IMV fault.
x
Check for Rail pressure (HP) sensor faults (P0192, P0193) and if present uses the rectification process of P0192;
P0193 fault.