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TIAGO/TIGOR AMT Gasoline
DTC Troubleshooting Guide
Version: 4.0
Date: 18-04-2017
Author: Sathi/Anupama
Page: 128 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.
39.
P1981 -02: Driver Engine Torque– Signal not valid
Overview:
ISO Code
P1981-02
Customer Symptom
Jerky or sluggish gearshifts
Fault Effects (On Vehicle)
Jerky or sluggish gearshifts
Lamp Status (If Any)
Transmission Fault Lamp OFF
Fault Detection Condition
This fault gets detected after Ignition On if EMS signals the
TCU that Driver requested torque information on CAN is
invalid.
Normal Operating Condition
EMS signals the TCU that driver requested torque information
on CAN is valid
Probable Trouble Area
Wiring Harness Connections / EMS / TCU
Healing Condition
200 milliseconds after valid sensor signal
Component Details:
Driver engine torque signal is transmitted via CAN bus to the TCU. In case of this particular DTC being set, it is expected that
an EMS component is at fault.
Preliminary Checks:
1) Loose/ Damaged EMS sensor/actuator 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
Check with the EMS diagnostic tool, are there EMS related
DTC’s present?
Rectify all DTC’s
related to EMS
(Refer 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
Fault Still Persists?
Recheck the above
steps
Follow the steps
again for
reconfirmation
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 driver engine torque and confirm that it
changes with accelerator pedal press.
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: