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: 697 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. P0103-35: Mass or Volume Air Flow Sesnor “A” Circuit High – Air mass meter (signal high time above threshold) Overview: DTC Description (User Friendly) Air mass meter (signal high time above 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) or Clear DTC Command with fault condition no more present. Fault Detection Condition (Root cause) The raw air mass value is greater than threshold1 (Signal High time greater than 833.35 m sec) Normal Operating Condition No Fault / Signal high time < 833.35 m sec. Probable Trouble Area 1. Mass air flow sensor signal shorted to battery supply 2. Mass air flow sensor signal circuit shorted to the fused Main power supply circuit. 3. High resistance in the MAF sensor ground circuit 4. Intake Air system leak / restriction 5. EGR System leak 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 discontinuity if noticed.
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