DSD Information System
Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (2GR-FKS) - Diagnostic Codes (1 Of 6) >> SFI System >> DTC P0100-12: Mass or Volume Air Flow Sensor "A" Circuit Short to Battery; DTC P0100-14: Mass or Volume Air Flow Sensor "A" Circuit Short to Ground or Open [12/2019 - 10/2022] >> Description

DTC P0100-12: Mass or Volume Air Flow Sensor "A" Circuit Short to Battery; DTC P0100-14: Mass or Volume Air Flow Sensor "A" Circuit Short to Ground or Open [12/2019 - 10/2022]: Description

The mass air flow meter sub-assembly is a sensor that measures the intake air volume using the following built-in components:

Intake air flows over the temperature sensor (before heater), the heater, and then the temperature sensor (after heater) on the silicon chip sensor in the by-pass passage. As the intake air is warmed up when it is exposed to the heater, the temperature of the intake air flowing over the temperature sensor (after heater) is higher than that over the temperature sensor (before heater). The difference in temperature of the intake air at each temperature sensor varies depending on the velocity of the intake air that flows over the silicon chip sensor. The temperature sensor bridge circuit detects the difference in temperature and the control circuit converts it into a pulse signal and outputs it to the ECM. When the temperature detected by the temperature sensor (before heater) is higher than that detected by the temperature sensor (after heater), backflow of the intake air is detected.

The ECM calculates the intake air amount based on the pulse signal received from the mass air flow meter sub-assembly, and uses it to determine the fuel injection duration necessary for an optimal air-fuel ratio.

The heater control bridge circuit includes temperature sensors and power transistor, and maintains the heater temperature at a specific temperature.

HINT: 

When DTCs is stored, the ECM enters fail-safe mode. During fail-safe mode, the ECM calculates the fuel injection duration based on the engine speed and throttle valve angle. Fail-safe mode continues until a pass condition is detected.

GTY899962Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
*a Temperature Sensor (Before Heater) *b Temperature Sensor (After Heater)
*c Heater *d Silicon Chip Sensor
*e Air Flow - -
DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory Note
P0100-12 Mass or Volume Air Flow Sensor "A" Circuit Short to Battery The mass air flow meter sub-assembly output frequency is higher than 9.8 kHz for 3 seconds or more (1 trip detection logic).
  • Open or short in mass air flow meter sub-assembly circuit
  • Mass air flow meter sub-assembly
  • ECM
Comes on DTC stored SAE Code: P0103
DTC for Mexico Models:
- Applies
P0100-14 Mass or Volume Air Flow Sensor "A" Circuit Short to Ground or Open The mass air flow meter sub-assembly output frequency is less than 0.1 kHz for 3 seconds or more (1 trip detection logic).
  • Open or short in mass air flow meter sub-assembly circuit
  • Mass air flow meter sub-assembly
  • ECM
Comes on DTC stored SAE Code: P0102
DTC for Mexico Models:
- Applies