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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: 628 of 1052
Copyright ©
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.
P16AB-26: Cruise control disabled for high deceleration
Overview:
DTC Description (User Friendly)
Cruise control disabled for high deceleration
ECU Pin Number
K035, K010, 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 deceleration 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 Up gradients
When Cruise active, Brake switch connector dis-connected (EMS
does not receive brake active information) and user presses Brake
pedal.
When Cruise active, park brake engaged
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 up gradients with cruise active.
4. Check with customer whether any vehicle deceleration has happened with cruise active and no Brake pedal press
on flat road. If yes, confirm that engine power loss happened
5. Check for damage of pins at ECU connector.
Trouble Shooting:
Step Checks
IF YES
IF NO
1
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
deceleration is
observed when
cruise active
Go to next step