TIAGO

TIAGO AMT Gasoline

DTC Troubleshooting Guide

Version: 2.0

Date: 06-06-2016

Author: Sathi/Anupama

Page: 191 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.

60.

P1889-04: Shift electrovalve Open Circuit

Overview:

ISO Code

P1889-04

Customer Symptom

Transmission Fault Lamp ON, No gearshifts, Vehicle not

cranking, sudden shift to neutral while driving

Fault Effects (On Vehicle)

No gearshifts, Vehicle not cranking, sudden shift to neutral

while driving, no EOL selftuning

Lamp Status (If Any)

Transmission Fault Lamp ON

Fault Detection Condition

This fault gets detected after Ignition On when shift

electrovalve is commanded OFF and an open circuit is

detected on the valve.

Normal Operating Condition

TCU does not detect open circuit

Probable Trouble Area

TCU mountings/ valve body damage / Electro valve / TCU

Healing Condition

50 milliseconds after valid detection of healed condition

Component Details:

The Shift electro valve is a proportional flow control solenoid valve which drives linear motion of the hydraulic shift selection

actuator. This component is mounted on the valve body and makes internal electrical contact with the TCU.

Preliminary Checks:

1) Loose/ Damaged Connections between Electro valve and TCU.

2) Loose/ Damaged mechanical fitments of TCU (TCU to valve body mounting).

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

Trouble Shooting:-

Step Checks

IF YES

IF NO

Unmount and remove the TCU from the valve body. Inspect

the condition of the Shift Electrovalve (EV3) (refer fig

below). Is the Valve or valve pins visibly undamaged?

Go to Step 2

Replace the

electrovalve/Valve

Body.

Inspect the Shift Electrovalve connector on TCU main

board (refer fig below) for loose fit/disconnection/pin

damage. Is the Electrovalve connected properly?

Go to Step 3

Fit the TCU to

valve body back

ensuring proper

contacts.

If TCU side

connector damage

then replace the

TCU.

If Problem persists, Replace the valve body and then if still

persists, replace TCU

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: