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TIAGO/TIGOR AMT Gasoline
DTC Troubleshooting Guide
Version: 4.0
Date: 18-04-2017
Author: Sathi/Anupama
Page: 137 of 427
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.
42.
P0703 -02: Brake switch input circuit – Signal not valid
Overview:
ISO Code
P0703-02
Customer Symptom
Transmission Fault Lamp ON
Creeping inactive,
Fault Effects (On Vehicle)
Creeping inactive,
Lamp Status (If Any)
Transmission Fault Lamp ON
Fault Detection Condition
This fault gets detected after Ignition On if EMS signals the
TCU that brake pedal information on CAN is invalid.
Normal Operating Condition
EMS signals the TCU that brake pedal information on CAN is
valid
Probable Trouble Area
Wiring Harness Connections / EMS / TCU
Healing Condition
200 milliseconds after valid sensor signal
Component Details:
Brake switch is connected to the EMS. Brake pedal position signal is transmitted by EMS via CAN bus to the TCU.
Preliminary Checks:
1) Loose/ Damaged Brake pedal switch Connections.
2) Check for damage or back out of pins at EMS connector and TCU connector.
3) Check correct fitment of ground cable connections on vehicle chassis.
Trouble Shooting:-
Step Checks
IF YES
IF NO
1.
Is there any rust/oxidation observed on
EMS or TCU connectors?
Clean the Rust or repair or
replace
Go to Step 2
2
Diagnose the Brake pedal input to EMS
(Refer EMS service manual), is there a
problem with Brake pedal switch or switch
to EMS connection?
Ensure correct connection of
brake pedal input to EMS as
per EMS service manual.
Go to step 3
3
Is TCU power connections on TCU
connector pins 5, 1, 3? Specifically check
Ignition supply toggling with key on/off.
Go to Step 4
Check and rectify
harness power
connections.
4
Connect the EMS diagnostic tool and check
the value of brake pedal position with
pressed and unpressed pedal, are correct
values observed?
Follow the steps again for
reconfirmation
Recheck the above
steps
DTC’s confirmation:-
After rectification, clear all DTC’s and ensure the following points by referring TCU parameters using TML diagnostic tool
before handing over to customer.
After key and engine ON with TML TCU diagnostic tool connected, monitor the brake press status and confirm that it
changes from about 0 unpressed to 1 when pressed fully.
Drive the vehicle through all gears in both Automatic and Manual modes.
Ensure no DTC is active and Transmission Fault Lamp is OFF.
Circuit Schematic Diagram: