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Q5/X451 FATC
DTC Troubleshooting Data
Version: 1.0
Date: 16-Oct-2018
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.
Author: ERC
Page: 11 of 202
B1F23-11:- Evaporator Temperature Sensor Signal - Circuit Short to Ground;
ISO Code
B1F23- 11
Customer Symptom
No cooling
Fault Effects (On Vehicle)
Evaporator temperature cannot be evaluated, hence
cooling cannot be achieved
Lamp Status (If Any)
AC shall be OFF, Evaporator sensor default value shall be
taken as OAT if Air inlet is Fresh / Incar Temp id Air inlet is
Recirc
Fault Detection Condition
Evaporator Temperature Sensor Circuit - Circuit Short to
Ground
Normal Operating Condition
Open Sensor connection and measure voltage between the
terminals of the wiring connector (Signal and GND) to
check if it measures 4-5V.
Probable Trouble Area
The sensor wiring is shorted to ground
Healing Condition
1) If the values seen on the diagnostics tool in read ECU
parameters is not getting updated then replace the sensor
2) If there is a continuity between the sensor signal and
ground lines correct the wiring harness (wiring harness
short to ground)
Component Details:
Evaporator temperature sensor is used to measure the evaporator core temperature .The evaporator cools the
refrigerant in the HVAC system .Since the evaporator core operates at temperatures very close to 0 DegC, it is
important to have an accurate and robust thermistor to measure its temperature to prevent the core from freezing. A
frozen core could result in costly damage to the evaporator core and diminished HVAC operation so that the cabin
temperature can no longer be controlled
Preliminary Checks:
1.
Switch On Ignition. Check sensor and its connector located at center position of lower case of the HVAC unit.
2.
Read Evaporator Temperature
Evaporator Temperature Sensor Signal Input
sensor ECU from the diagnostic tool