TIAGO

TIAGO AMT Gasoline

DTC Troubleshooting Guide

Version: 2.0

Date: 06-06-2016

Author: Sathi/Anupama

Page: 271 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.

85.

P190D-01: Gearbox System Clutch over speed

Overview:

ISO Code

P190D-01

Customer Symptom

Transmission Fault Lamp OFF

sudden shift to neutral while driving

Fault Effects (On Vehicle)

sudden shift to neutral while driving

Lamp Status (If Any)

Transmission Fault Lamp ON

Fault Detection Condition

This fault gets detected after Ignition On during vehicle

running if the clutch speed crosses a threshold

Normal Operating Condition

TCU monitors that the clutch speed is within operable safe

limits

Probable Trouble Area

Gear Electro valve / TCU / Gearbox

Healing Condition

Fault is cleared on next ignition Power ON

Component Details:

In an AMT system, the gear shifting is actuated through 3 electrovalves viz. 2 gear electrovalves for shifting between odd and

even gears and 1 shift electrovalves for shifting between ranks.

Preliminary Checks:

1) Loose/ Damaged Valve body and TCU mountings.

2) Check for damage or back out of pins at TCU connector.

3) Check visibly for kit Oil leakage and ensure with diagnostic tool that kit oil pressure is in range 38 - 51 bar

4) Check for mechanical damage to the Valve body (MGA), kit and gearbox mechanical fitments

5) Check correct fitment of ground cable connections on vehicle chassis.

Trouble Shooting:-

At first occurrence of this DTC, clear the DTC and drive the vehicle through all gears for ~5 kms, on repeat occurrence of this

DTC check the following.

Step Checks

IF YES

IF NO

Check the kit & gearbox assembly for

mechanical damage, stuck gear actuator,

synchro ring damage, fork damage, gear

damage, lubrication etc?

Go to Step 2

Rectify/replace the

gearbox

Check gear electrovalves electrical

connections by following same procedure

P0750 & P0755, Are

electrical connections OK?

Go to Step 3

Establish continuity by

rectifying harness

connections as per the

circuit schematic

Using TCU diagnostic tool, initiate a grid

learning procedure

Are gears engaging and disengaging freely

and grid learning is successfully executed?

Recheck the above steps

Replace parts in following

order and re-verify:

1>Valve body (MGA)

2>Gearbox

3>Entire Transmission

the following points by referring TCU parameters using TML diagnostic tool

before handing over to customer.

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: