NEXON 3.0 EV DTC Troubleshooting Document for VCU Version: 2.0 Date: 22-Sep-2023 Copyright © TATA MOTORS Ltd. This document must not be used in anyway, such as copying and redistributing to third parties, without the consent of author. P302D - 94: - HV Battery Cooling Pump dry run detected - unexpected operation Overview: ISO Code P302D - 94 Customer Symptom Coolant pump not working Fault Effects (On Vehicle) No coolant circulation in HV battery HV battery over temperature while in crank or charging (subsequent effect) Lamp Status (If Any) Service Indicator Lamp is ON, on the cluster If temperature of battery is reached above operable threshold, battery over-heat tell-tale is seen on cluster Fault Detection Condition As per Bosch base software, battery cooling pump is running dry Normal Operating Condition Low voltage battery voltage between 8V – 14V. Recommended coolant present until prescribed level of coolant tank. Pump operated at requested duty cycle Probable Trouble Area 1. Coolant not present in the BCS coolant tank 2. Leakage in coolant line 3. No/improper de-aeration of coolant line Healing Condition 1. POR (Power-On Reset, i.e. remove the negative terminal of LV battery for 2s) 2. Adjust the Battery cooling pump PWM Duty Cycle as per troubleshooting table Component Details: The BCS pump operates on LV supply. It has the following electrical connections: Switched supply voltage (+ve) UPump, Input signal / diagnosis connection (S = PWM) and Ground (terminal 31, GND, -ve). The pump contains a microcontroller, which decodes the input PWM signal, calculates corresponding set speed of the pump and controls the motor. The pulse-width modulated (PWM) signal is defined by VCU. The operating mode and the set speed of the motor represents frequency (fin) and Duty Cycle (DCin) of the signal.
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