TIAGO/TIGOR AMT Gasoline DTC Troubleshooting Guide Version: 4.0 Date: 18-04-2017 Author: Sathi/Anupama Page: 230 of 427 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. 73. P2904-01: Clutch System – Not opening before shift Overview: ISO Code P2904-01 Customer Symptom No gearshifts, Automatic gear shift mode disabled (manual mode always) Fault Effects (On Vehicle) No gearshifts, Automatic gear shift mode disabled Lamp Status (If Any) Transmission Fault Lamp OFF Fault Detection Condition This fault gets detected after Ignition On before a gearshift when clutch is commanded open but found to be not responding. Normal Operating Condition TCU detects correct clutch response during clutch opening for gearshift Probable Trouble Area Clutch Electro valve / TCU / Clutch Healing Condition Fault is cleared on next successful gear shift Component Details: In an AMT system, the clutch is electro-hydraulically controlled by the TCU. Preliminary Checks: 1) Loose/ Damaged Valve body and TCU mountings. 2) Check for damage or back out of pins at TCU connector. 3) Check visibly for kit Oil leakage and ensure with diagnostic tool that kit oil pressure is in range 38 - 51 bar 4) Check for mechanical damage to the clutch housing, clutch actuator mechanical fitments 5) Check correct fitment of ground cable connections on vehicle chassis. Trouble Shooting:- Step Checks IF YES IF NO 1. Check the clutch assembly and AMT clutch lever interface for mechanical damage, stuck particle, lubrication loss etc? Go to Step 2 Rectify/replace the component 2. Check clutch electrovalve electrical connections by following same procedure as for DTC – P0900. Are electrical connections OK? Go to Step 3 Establish continuity by rectifying harness connections as per the circuit schematic 3. Using TCU diagnostic tool, initiate clutch actuation routine.Monitor “clutch position Actuator” Variable and confirm that it changes from engaged (~xxx mm) to disengaged (yyy mm) position. (Alternately visibly check the clutch lever movement with actuation command.) Is the clutch engaging and disengaging freely? Recheck the above steps Replace the valve body (Mechatronic gear Actuator), if fault persists then Replace Kit DTC’s confirmation:- After rectification, clear all DTC’s and ensure the following points by referring TCU parameters using TML diagnostic tool before handing over to customer. 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:
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