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Q501 4 Cylinder MT Application
DTC Troubleshooting Data
Version: 0.1
Date: 21-Sep-2018
Prepared By: Mithi Prasad, Sarang Kulkarni, Manish Gupta
Checked By: Yogesh Jadhav
Approved By: Satish Kumar P
Page: 617 of 1052
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.
P014D-92: O2 sensor slow response – lean to Rich Bank 1 sensor 1 – Lambda sensor upstream dynamic fault
(lean to rich transitions)
Overview:
DTC Description (User Friendly)
Lambda sensor upstream dynamic fault (lean to rich
transitions)
ECU Pin Number
A046, A104, A105, A083, A084
Customer Symptom
MIL ON1, CEL OFF. Low fuel efficiency
Fault Effects (On Vehicle)
Low fuel efficiency and Engine performance impacted.
Lamp Status (If Any)
MIL ON1. MIL will be off after 3 warm cycles (drive cycle with
22 deg of coolant temperature increase is a Warm up cycle).
Fault Detection Condition (Root cause)
Dynamics fault (Transition) of O2−signal dynamics (lean to
rich transitions; sensor 1, bank 1)
Normal Operating Condition
Fault condition not present
Probable Trouble Area
O2 Sensor
Wiring Harness connections between O2 sensor and EMS
ECU.
Defective Catalytic converter
Leaks in Exhaust path
EMS ECU
Healing Condition
Rectify the error
Clear through diagnostic tool
Ignition OFF & ON
Component Details:
O2 / oxygen sensors are constructed using a zirconium dioxide-sensing element, which is protected
by a specially designed, vented, steel housing. Platinum electrodes are used to attach the sensing element to wire leads
in the O2 sensor wiring harness, which is connected to the PCM. The PCM is supplied with an electrical signal according
to the percentage of oxygen particles in the engine exhaust compared to the oxygen content of ambient air.
Exhaust gases are pushed into the exhaust manifold(s) and down pipe(s) where they flow over/through the upstream O2
sensor. Exhaust flows through the O2 sensor vent holes (in the steel housing) and across the sensing element and
ambient air is drawn through the wire lead cavities where it is trapped in a small chamber in the center of the sensor. The
exhaust, forcing the oxygen ions to produce (energy) voltage, heats the trapped ambient air (in the chamber).
Deviations between the concentration of oxygen molecules in ambient air (drawn into the center cavity of the O2 sensor)
and the concentration of oxygen ions in the spent exhaust gases, cause the heated oxygen ions inside the O2 sensor to
jump between platinum layers very rapidly and repetitiously. Fluctuations in voltage occur as the rushing oxygen ions
jump between the layers of the platinum electrodes. These variations in voltage are identified by the PCM as changes in
exhaust oxygen concentration, which indicate that the engine is either running lean (too little fuel), or rich (too much fuel).
When more oxygen is present in the exhaust (lean condition), the voltage signal from the O2 sensor is low and is higher
when less oxygen is present in the exhaust (rich condition). This data is used by the PCM primarily to calculate fuel
delivery and ignition timing strategy but also to monitor catalytic converter efficiency.
Preliminary Checks:
1. Check whether the customer voice / view about the issue is matching with the fault effects mentioned in above
Table. If yes, go ahead with next steps. If not, check for other DTC’s presence.
2. Check whether other customers report similar complaints earlier. If yes, perform the preliminary checks with
respect to earlier issue closure.