TIAGO

TIAGO AMT Gasoline

DTC Troubleshooting Guide

Version: 2.0

Date: 06-06-2016

Author: Sathi/Anupama

Page: 131 of 424

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.

40.

P2906 -04: Engine Wish Torque Signal not valid

Overview:

ISO Code

P2906-04

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 Engine wish torque information on CAN is invalid.

Normal Operating Condition

EMS signals the TCU that Engine wish torque information on

CAN is valid

Probable Trouble Area

Wiring Harness Connections / EMS / TCU

Healing Condition

200 milliseconds after valid sensor signal

Component Details:

Engine wish 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

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

to EMS (Refer EMS

service manual)

Go to step 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.

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 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: