TIGOR AMT

TIAGO/TIGOR AMT Gasoline

DTC Troubleshooting Guide

Version: 4.0

Date: 18-04-2017

Author: Sathi/Anupama

Page: 59 of 427

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.

18.

P1852-02: Clutch Position/Hyd Press Sensor – Wrong supply voltage Vbatt Error

Overview:

ISO Code

P1852-02

Customer Symptom

Transmission Fault Lamp ON,

Loss of power while driving.

Engine not cranking

Engine stalling at low vehicle speeds

No gearshift

Fault Effects (On Vehicle)

Transmission going automatically to neutral while driving.

Engine not cranking

Engine stalling at low vehicle speeds

No gearshift

No EOL self-tuning.

Lamp Status (If Any)

Transmission Fault Lamp ON

Fault Detection Condition

This fault gets detected after Ignition On when the Engine is not cranking and

battery Supply voltage is in proper range and the clutch position/Hydraulic

Pressure sensor supply voltage is found to be higher than acceptable threshold.

Normal Operating

Condition

Clutch position/Hydraulic Pressure sensor supply voltage is regulated at 5 V by

TCU

Probable Trouble Area

Harness or connector damage/short, Sensor loose/damage/short, TCU internal

damage

Healing Condition

50 milliseconds after valid sensor signal

Component Details:

Clutch position/Hydraulic Pressure sensor supply voltage is regulated at 5 V by TCU. The clutch position sensor is supplied

through pin 12 (12 pin system connector) and hydraulic pressure sensor through internal TCU connection.

Preliminary Checks:

1) Loose/ Damaged TCU system connector (12 pin).

2) Check for any visible damage to TCU pins, clutch sensor/hydraulic pressure sensor and its pins.

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

Trouble Shooting:-

On first occurrence, clear the DTC and drive the vehicle for 2-3 kms, read the DTC again. On fault confirmed again, follow

below steps.

Step Checks

IF YES

IF NO

Is there any rust/oxidation/pin back out

observed on 12 pin system connector pins 1, 8

&12.

Clean the Rust or repair

or replace

Go to Step 2

Is there wiring harness electrical continuity

between 12 pin system connector pins 1,8

&12.to

Sensor connector pins 2,1 &3?

Go to Step 3

Establish continuity by

rectifying harness

connections as per the

circuit schematic

Are there any pins damaged at Clutch Sensor

Connector?

Replace the system

wiring harness.

Go to step 4

Is Clutch Sensor Supply Pin (pin 12 of 12 pin

system connector) Short circuited to

GND/Battery?

Repair the harness as per

the schematic

Go to Step 5

Unmount and remove the TCU from the valve

body. Inspect the condition of the Hydraulic

pressure sensor contacts (refer fig below). Are

the sensor contacts visibly undamaged?

Go to Step 6

Replace the Hydraulic

Pressure sensor/TCU.