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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: 128 of 202
B1F38-23:- Rear Defog Request Button -Signal Stuck Low
Overview:-
ISO Code
B1F38 – 23
Customer Symptom
Rear Defog Request Button cannot be manually
selected
Fault Effects (On Vehicle)
The Rear Defog switch is stuck and unable to ON/OFF
rear defog heater grids
Lamp Status (If Any)
If Rear Defog function was active prior to key jam
detection, then the rear defog request to BCM will
continue to transmitted as ON until BCM timeouts the
rear defog function
If Key Jam(Stuck) is cleared, Rear Defog can be
activated/deactivated along with supporting
conditions with the rear defog key press.
Fault Detection Condition
Rear Defog Request Button -Signal Stuck Low
Normal Operating Condition
Rear Defog push button shall be used to manually
switch ON/OFF the rear defog heater grids on the rear
window.
Probable Trouble Area
Mode switch component failure.
Healing Condition
Check and lubricate switch, replace control panel
Component Details:
Rear Defog
switch Button is shown in above image. The user shall be used
to manually switch ON/OFF the rear
defog heater grids on the rear window.
Preliminary Checks:
Switch On the IGN & perform the following check.
1) Connect the Diagnostics tool & check the DTC fault code
2) If the fault code exists, refer the corrective actions