NEXON DIAGNOSTIC MANUAL

OSPREY- Application

DTC Troubleshooting Data

Version: 4.0

Date: 10-02-2017

Prepared by: Mithipati Prasad

Checked by: G S Raju / Senthilnathan S

Page: 316 of 654

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: Low Speed (Top Fan) Fan Control - Short Circuit to Ground

Overview:

DTC Description as per ISO standard

Fan 1 Control Circuit Low.

ECU Pin Number

Customer Symptom

AC will not function.

Cooling fans will run in low speed continuously.

Engine over temperature warning lamp will turn on at lesser engine coolant

temperature (8 degrees less than normal condition).

Fault Effects (On Vehicle)

Radiator fan will remain run continuously.

SPCS injector learning will be disabled.

Threshold for Engine over temperature warning lamp turn ON will be

reduced.

Lamp Status (If Any)

CE lamp is on.

Fault Detection Condition

This DTC gets logged if the Low speed fan (Top fan) control pin of EMS

ecu gets short circuit to ground

Normal Operating Condition

When vehicle is soaked for 8 hours and Engine is cranked keeping AC off

then Cooling fans will be in Off condition.

Probable Trouble Area

Fan circuit wiring harness, Low Speed fan relay, HVAC, ECU, Wiring

harness

Component Details:

Cooling Fan circuit consists of two fans. With the help of Relays, cooling fans will be made to run either in Series (Low

Speed) or Parallel (High Speed). EMS will decide whether to turn the cooling fans in low speed or high speed based on

Engine coolant temperature & AC refrigerant pressure.

Preliminary Checks:

Check whether the customer voice / view about the issue is matching with the fault effects mentioned above. If

yes, go ahead with next steps. If not, check for other DTC’s presence.

Check whether similar complaints are earlier reported. If yes, perform the preliminary checks with respect to

earlier issue closure.

Loose/ Damaged Connections between low speed fan Relay and EMS ecu.

Loose/ Damaged Connections between low speed fan Relay and Battery supply or Ground.

Check for back out of pins & damage of pins at ECU connector.