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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: 309 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.
P0653: Sensor Reference Voltage “B” Circuit High
Overview:
DTC Description as per ISO standard
Sensor Ref
erence Voltage “B” Circuit
High
ECU Pin Number
76
Customer Symptom
Reduced torque mode gets activated.
Engine may not start, if already running then stops after few seconds with
engine vibrations.
Fault Effects (On Vehicle)
Disables EGR by setting desired rate to 0. This will affect EGRH rate,
EGRL rate, Throttle, Intake manifold pressure and boost pressure.
Engine speed limitation requested
Lamp Status (If Any)
CE lamp is on.
Fault Detection Condition
This DTC gets logged if the sensor supply Voltage 2 is less than lower
threshold.
Normal Operating Condition
Diagnostic tool display the Vref 2 status at ignition ON
Probable Trouble Area
ECU Main relay, ECU, Wiring harness
Component Details:
EMS ECU has two Internal 5 Volts power supplies. Power Supply 1 will provide input voltage to a group of
sensors
–
A. and Power Supply 2 will give input voltage to another group of Sensors-B.
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 the connection of sensors powered by sensor supply Voltage 2. Follow sensor supply voltage2 check /
rectification process.
x
Check for dirt / rust on the Accelerator pedal module connector. Rectify / Replace the connector if dirt / rust found.
x
Check for damage / pin back out of EMS ecu and Accelerator pedal module connector.
x
Check with diagnostic tool if the sensor supply voltage lies in between 4.75 V to 5.35 V