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 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. 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 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 acceleration is observed when cruise active Go to next step 2 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
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