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: 105 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.

P0038-12: HO2S2 Heater Control Circuit(Bank 1 sensor 2) – Circuit Short to Battery

Overview:

ISO Code

P0038 – 12

Customer Symptom

Drivability will get affected during idle and part Load conditions

Fault Effects (On Vehicle)

1. Vehicle running in Open loop initially for a longer time.

2. No effect on starting and driveability.

Lamp Status (If Any)

MIL ON after 3 drive cycle

Fault Detection Condition

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

pin is short Circuited to battery supply.

Normal Operating Condition

Healthy wiring harness connections between EMS ecu and downstream

oxygen Sensor.

Probable Trouble Area

Wiring Harness Connections / Sensor

1.Heater Line shorted to battery for upstream sensor

2. Faulty Lambda sensor

3. Faulty ECU.

Healing Condition

Engine running and 3 drive cycles

Fault present 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.