Vehicle Platform & ECU Name DTC Troubleshooting Data Ver: 1.0 Date: 30/11/2019 Author: ERC Page 385 of 610 Copyright by TATA MOTORS Ltd. This document must not be used in any way, such as copying and redistributing to third parties, without our consent Trouble Shooting: Step Checks IF YES IF NO 1. Are Relay Contacts weld / Stuck Open Replace the Relay Go to Step 2 2. Is there wiring harness electrical continuity between ECU pin B71 & AC relay pin 3. Also Check continuity between the Main Relay supply and the AC relay pin 1. Also check continuity from AC Relay pin 1 to GND. Go to Step 3 Establish continuity by rectifying harness connections as per the circuit schematic 3. Are there any pins damaged at EMS ECU Connector Replace the connector or wiring harness Go to step 4 4 Are there any pins backed out from the EMS ECU Connector Rectify/Replace Connectors Go to Step 5 5 Is relay getting Supply at its pin 3 Go to Step 6 Repair the harness as per the schematic 6 Is AC Relay control Pin B71, circuit short to ground? Repair the harness as per the schematic Go to Step 7 7 Is AC Compressor Working or stalled Rectify / Replace AC Compressor Go to Step 8 8 Fault Still Persists? Replace relay and then if Fault still persists then Call Hot Line Follow the steps again for reconfirmation DTC’s confirmation: After rectification, ensure the following points by referring engine parameters using TML diagnostic tool before handing over to customer. Perform Actuator test of AC Relay. Test should be successful. Turn Off the AC request, AC Compressor shall be disengaged / Off.
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