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Nexon Gasoline – EMS ECU Bosch
DTC Troubleshooting Manual
Version: 0.1
Date: 26-08-2017
Prepared By: Sunu S Babu/Yogesh Jadhav
Checked By: Yeshwant Jadhav
Approved By: Satish Kumar
Document Part No: 2921 02 224 A1736
Page: 826 of 1203
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.
P0691-11: A/C Fan Low Speed Relay Control Circuit Low – Circuit Short to Ground
Overview:
ISO Code
P0691-11
Customer Symptom
A/C Fan ON Continuously, Fuel Efficiency decreases, A/C will not work,
Nothing to do with limphome
Fault Effects (On Vehicle)
A/C Fan will run Continuously, Fan might get damaged, Fuel Consumption
Decreases due to additional load of Fan, A/C will not work, nothing to do with
limphome
Lamp Status (If Any)
CE lamp ON after 1 drive cycle
Fault Detection Condition
This fault gets logged if the Slow speed fan control pin of EMS ECU is short
Circuited to Ground
Normal Operating Condition
Healthy Wiring Harness connections between A/C Fan relay and EMS ECU,
Relay Fully Operational, Healthy Wiring Harness connections from Relay to
Main Relay supply and Ground.
Probable Trouble Area
Improper Wiring Harness Connections, faulty Relay, Faulty fan
Healing Condition
Ignition key on and 1 drive cycles after fault rectification
Fault permanent deletion
1. Clear DTC Command form Scan tool
2. Stack Over Flow.
3. 40 warm up cycles.
4. ECU Flashing.
5. ECU Power-Fail
Component Details:
Radiator fan is driven by EMS ECU via a relay, Fan will be ON, when the EMS ECU energizes the coil of fan relay.
Preliminary Checks:
1) Loose/ Damaged Connections between Fan Relay and EMS ECU.
2) Loose/ Damaged Connections between Fan Relay and Battery supply and Ground.
3) Check for back out of pins at ECU connector.
4) Check for damage of pins at ECU connector.
5) Check the continuity from Relay to the ECU pin and from battery / Main Relay Supply to Fan Relay.