TIAGO

TIAGO AMT Gasoline

DTC Troubleshooting Guide

Version: 2.0

Date: 06-06-2016

Author: Sathi/Anupama

Page: 218 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.

69.

P081A-02: Cranking Enable Short to supply

Overview:

ISO Code

P081A-02

Customer Symptom

Transmission Fault Lamp ON,

Transmission shifting to neutral when engine is OFF

Fault Effects (On Vehicle)

Transmission shifting to neutral when engine is OFF

Lamp Status (If Any)

Transmission Fault Lamp ON

Fault Detection Condition

This fault gets detected after Ignition On when cranking

enable output is commanded OFF and a short circuit to

ground or open circuit is detected.

Normal Operating Condition

TCU does not detect short to ground or open circuit

Probable Trouble Area

Wiring Harness Connections / Electric motor / TCU

Healing Condition

50 milliseconds after valid detection of healed condition

Component Details:

Cranking enable output is a digital output from TCU to EMS which is driven low to allow EMS to crank the Engine safely.

Preliminary Checks:

1) Check for damage/loose fit or back out of pins at TCU 28 pin vehicle connector, & EMS connector.

2) Check for visible damage to TCU or EMS pins.

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

Trouble Shooting:-

Step Checks

IF YES

IF NO

Is there any rust/oxidation/damage

observed on TCU 28 pin vehicle connector,

& EMS connector Terminals?

Clean the Rust or repair or

replace

Go to Step 2

Is there wiring harness electrical continuity

between TCU pin 16 to EMS pin 107? Also

check for any short to battery or ground on

pin 16.

Go to Step 3

Establish continuity by

rectifying harness

connections as per the

circuit schematic

Check the TCU ignition and power

connections on Pins 5, 1 and 3 respectively.

Check for ignition pin toggling to 12 V with

ignition key On-Off. Connections are OK?

Go to Step 4

Establish continuity by

rectifying harness

connections as per the

circuit schematic

4. Replace the TCU, problem persists?

Replace the EMS

recheck the above steps

the following points by referring TCU parameters using TML diagnostic tool

before handing over to customer.

Check for proper cranking behavior of the vehicle. i.e. cranking only in neutral gear with brake pressed.

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: