NEXON DIAGNOSTIC MANUAL

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: 288 of 1203

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.

P0140-2F: O2 Sensor Circuit Signal Line Short to Heater Line(Bank 1 Sensor2) - Signal Erratic

Overview:

ISO Code

P0140 – 2F

Customer Symptom

Drivability will get affected during idle and part Load conditions

Fault Effects (On Vehicle)

1. No apprehensive feeling in idle.

2. No effect in drivability

Lamp Status (If Any)

MIL ON after 3 drive cycles

Fault Detection Condition

This fault gets logged if EMS ECU finds the downstream oxygen Sensor

signal pin of EMS is short Circuited to its heater control pin.

Normal Operating Condition

Wiring Harness connections as per schematic for downstream oxygen

Sensor.

Probable Trouble Area

Wiring Harness Connections / Sensor

Healing Condition

Engine running and 3 drive cycles

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:

Lambda Sensor:

The oxygen Sensor operates on the principle of galvanic oxygen concentration cell (Nernst cell) with

solid electrolyte (Nernst's principle). The ceramic sensing element is a conductor of oxygen ions from a temperature of

350 C. A heater is integrated on the sensing element. It is placed into the exhaust manifold. The sensing element

compares the residual oxygen content in the exhaust gas with the oxygen content in the reference atmosphere (air

surrounding the sensing element). This gives an output voltage between 100mV (lean exhaust gas) to 800mV (rich

exhaust gas), depending on whether the exhaust gas is lean or rich.

Preliminary Checks:

1) Loose/ Damaged Connections between Sensor and EMS ECU.

2) Check for back out of pins at both Sensor connector and ECU connector.

3) Check for damage of pins at both Sensor connector and ECU connector.

4) Check the continuity from Sensor connector pins to the ECU pins.