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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: 693 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.
P0102-32: Mass or Volume Air Flow Sensor “A” Circuit Low – Air mass meter (signal high time below threshold)
Overview:
DTC Description (User Friendly)
Air mass meter (signal high time below threshold)
ECU Pin Number
K086, K087
Customer Symptom
MIL ON
Fault Effects (On Vehicle)
-
Lamp Status (If Any)
MIL ON.
MIL OFF: After 3 warm up Cycles (Drive Cycle with coolant
temperature increase by 22 degrees is a warm up cycle) or
Clear DTC Command with fault condition no more present.
Fault Detection Condition (Root cause)
The raw air mass value is less than threshold2 (Signal low
time < 71.4 msec).
Normal Operating Condition
No Fault. Signal high time > 71.4 msec.
Probable Trouble Area
1. Main Power Relay Supply to Sensor not available
2. Sensor Air Flow Signal to EMS open circuited
3. Sensor Air Flow Signal to EMS - short circuited to Ground.
4. MAF Sensor Signal wire short circuited with sensor ground
pin.
6. MAF sensor
7. EMS ECU
Healing Condition
Rectify the error
Clear through diagnostic tool
Ignition OFF & ON
Component Details:
The operating principle is based on the heating of a diaphragm (sensitive element
containing two resistances upstream and downstream of the support) in a by-pass duct through which the engine intake
air flows. The hot film membrane is maintained at constant temperature (about 120 °C higher than the incoming air
temperature) by the specific heating resistance controlled by the management electronics. The mass of air passing
through the by-pass duct, giving off heat to the membrane, thermally unbalances the two resistances to an extent directly
proportional to the mass of the incoming fluid, an imbalance that is translated through the control circuit into a resistance
variation, electronically processed and translated into a frequency value to be sent to the engine management control unit.
The imbalance in the resistance value also makes it possible to determine the direction of the column of air. As far as the
air temperature information is concerned, it is sent to the engine management control unit via a dedicated pin in the form
of a duty cycle signal (rectangular wave). The value of the duty is proportional to the value of the temperature.
Preliminary Checks:
1. 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.
2. Check whether similar complaints are earlier reported. If yes, perform the preliminary checks with respect to
earlier issue closure.
3. Check for any other faults presence related to ECU Internal power supplies; Follow rectification process for those
faults, before proceeding further.
4. Check for electrical continuity between ECU to AMF connector as per circuit schematic and rectify electrical dis-
continuity if noticed.
5. Check inlet air circuit for clogging; wrong assembly/fitment / leakages etc; clean the inlet air circuit and remove
any clogging and remove leakage paths.