TIAGO AMT Gasoline DTC Troubleshooting Guide Version: 2.0 Date: 06-06-2016 Author: Sathi/Anupama Page: 128 of 424 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 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 - 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:
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