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: 852 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. P0481-13: Fan2 Control Circuit – Cooling Fan 2 (open circuit) Overview: DTC Description (User Friendly) Cooling Fan 2 (open circuit) ECU Pin Number K040 Customer Symptom MIL ON, Cooling Fans operate only in Low Speed Fault Effects (On Vehicle) Cooling Fans operate only in Low Speed Lamp Status (If Any) MIL ON Fault Detection Condition (Root cause) The hardware detects an open load error on the digital output power stage for the Fan actuator – K040 Normal Operating Condition No Fault Probable Trouble Area Check, whether there is dis-continuity in wiring harness between High Speed fan Relay and EMS ECU. High Speed fan relay faulty, EMS ECU faulty Healing Condition Rectify the error Clear through diagnostic tool Ignition OFF & ON Component Details: Cooling Fan circuit consists of a single fan. With the help of Relays and Resistor (to drop the input power available to Fan for operating it in low speed), cooling fan will be made to run either in Low Speed or High Speed. EMS will decide whether to turn the cooling fans in low speed or high speed based on Engine coolant temperature & AC refrigerant pressure (based on Trinary pressure switch inputs). 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. Loose/ Damaged Connections between high speed fan Relay and EMS ECU. 4. Loose/ Damaged Connections between high speed fan Relay and Battery supply or Ground. 5. Check for proper installation of high speed fan relay in fuse box. 6. Check for damage of pins at ECU connector. Trouble Shooting: Step Checks IF YES IF NO 1 Check Whether the high speed fan relay is installed on Vehicle Go to Next Step Fit high speed fan Relay 2 Check for any mechanical damage in high speed fan Relay Replace faulty Relay Go to next step 3 Is there wiring harness electrical continuity between ECU pin K040 & AC relay pin 3. Also, Check continuity between the Main Relay supply and the low speed fan relay pin 1. Also check continuity from low speed fan Relay pin 1 to GND. Go to next step Rectify the wiring harness connections as per the circuit schematic. 4 Are there any pins damaged at EMS ECU Connector Replace the Go to Next Step
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