HARRIER BOOK 2

Q501 4 Cylinder MT Application

DTC Troubleshooting Data

Version: 0.1

Date: 21-Sep-2018

Prepared By: Mithi Prasad, Sarang Kulkarni, Manish Gupta

Checked By: Yogesh Jadhav

Approved By: Satish Kumar P

Page: 626 of 1052

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.

P16AA-27: Cruise control / speed limiter by driver reversible disabling for high acceleration – Signal Rate of

Change above threshold

Overview:

DTC Description (User Friendly)

Cruise control / speed limiter by driver reversible disabling for high

acceleration

ECU Pin Number

K029,K033

Customer Symptom

MIL OFF, CEL OFF. Cruise control will get inactive

Fault Effects (On Vehicle)

Cruise Control will get inactive

Lamp Status (If Any)

Fault Detection Condition (Root cause)

This fault gets detected if the vehicle acceleration is greater than 2.5

m/sec^2 for 0.5 sec when cruise active.

Normal Operating Condition

No Fault

Probable Trouble Area

Vehicle travelling in steep down gradients

Engine mal-function (Generates more power without Acc. Pedal

input)

EMS ECU faulty.

Healing Condition

Rectify the error

Clear through diagnostic tool

Ignition OFF & ON

Component / Function Details:

EMS ECU controls the Vehicle Speed to the User Set cruise speed provided other pre-conditions are satisfied. User

has got the Cruise switch interface on Steering wheel to Enable the function, Set / Resume cruise target speed and

cancel cruise.

Preliminary Checks:

1. Check whether the customer voice / view about the issue is matching with the fault effects mentioned in above

Table. If yes, go ahead with next steps. If not, check for other DTC’s presence.

2. Check whether other customers report similar complaints earlier. If yes, perform the preliminary checks with

respect to earlier issue closure.

3. Check, whether the fault has got logged when vehicle is driven on steep down gradients with cruise active.

4. Check with customer whether any vehicle acceleration has happened with cruise active and no accelerator pedal

press on flat road. If yes, confirm that it is EMS ECU SW malfunction or HW malfunction and call hot line.

5. Check for damage of pins at ECU connector.

Trouble Shooting:

Step Checks

IF YES

IF NO

Check whether vehicle is driven on steep gradients with

cruise active.

Convey driver that it

is a safety feature to

de-activate cruise

when rapid

acceleration is

observed when

cruise active

Go to next step

Check for Engine mal-function, generating torque even

without Acc. Peda Pres. Found mal-function?

Check for any other

faults presence and

Go to next step