TIAGO AMT Gasoline DTC Troubleshooting Guide Version: 2.0 Date: 06-06-2016 Author: Sathi/Anupama Page: 206 of 424 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. 65. P185C-01: Hydraulic pump Supply Short to ground Overview: ISO Code P185C-01 Customer Symptom Transmission Fault Lamp ON, No gearshifts, sudden shift to neutral while driving Engine not cranking Fault Effects (On Vehicle) No gearshifts, sudden shift to neutral while driving Engine not cranking Lamp Status (If Any) Transmission Fault Lamp ON Fault Detection Condition This fault gets detected after Ignition On when hydraulic pump output supply is commanded ON and a short circuit to ground is detected on the supply. Normal Operating Condition TCU does not detect short to ground Probable Trouble Area Wiring Harness Connections / Electric motor / TCU Healing Condition 1000 milliseconds after valid detection of healed condition Component Details: Hydraulic pump supply output is used to drive the hydraulic pump which supplies pressurized hydraulic oil for kit actuators. Preliminary Checks: 1) Loose/ Damaged Connections between hydraulic pump motor and TCU. 2) Check for damage or back out of pins at TCU 12 pin system connector, hydraulic pump motor connector & TCU pins. 3) Check for visible damage to Electric motor. 4) Check correct fitment of ground cable connections on vehicle chassis. Trouble Shooting:- Step Checks IF YES IF NO 1. Is there any rust/oxidation/damage observed on Electric Motor (refer fig below)/ TCU /12 pin system connector Terminals? Clean the Rust or repair or replace Go to Step 2 2. Is there wiring harness electrical continuity between TCU pin 7 to electric motor connector pin? Also check for any short to battery or ground on pin 7. Go to Step 3 Establish continuity by rectifying harness connections as per the circuit schematic/replace the system pigtail harness if defective. 3 Check the TCU ignition and power connections on Pins 5, 1 and 3 respectively. Check for ignition pin toggling to 12 V with ignition key On-Off. Connections are OK? Go to Step 4 Establish continuity by rectifying harness connections as per the circuit schematic 4. With all electrical connections fully connected and only the motor 1 pin connector open, monitor the voltage output at motor 1 pin connector. With the TML diagnostic tool, Actuate the hydraulic pump. Is 12 V observed at the motor connector after command ON for some time (~10 sec) and 0 V later? Go to step 5 Go to step 7 5 Refit the motor connector and With the TML diagnostic tool, Actuate the hydraulic pump. Clear the DTC and recheck the above steps. Go to step 6
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