DTC P0100, DTC P0102 & DTC P0103 Lexus ES XV30 facelift

Code Definition

1. DTC P0100: Mass Or Volume Air Flow Circuit
2. DTC P0102: Mass Or Volume Air Flow Circuit Low Input
3. DTC P0103: Mass Or Volume Air Flow Circuit High Input

Circuit Description

Hot wire mass air flow meter consists of a platinum hot wire, temperature sensor and control circuit installed in a plastic housing. Hot wire mass air flow meter works on the principle that hot wire and intake air temperature sensor, located in intake air by-pass of housing, detect any changes in intake air temperature. Hot wire is maintained at set temperature by controlling current flow through hot wire. This current flow is then measured as output voltage of mass air flow meter. Circuit is constructed so that platinum hot wire and temperature sensor provide a bridge circuit with power transistor controlled so that potential of A and B remains equal to maintain set temperature. (Scheme 176) If DTCs P0100 or P0102 are set, there is an open or short in mass air flow meter circuit for more than 3 seconds. If DTC P0103 is set, there is an open in mass air flow meter circuit for more than 3 seconds (E2G circuit) or short in mass air flow meter circuit for more than 3 seconds (+B circuit).

Scheme 176

Diagnostic Aids

1. After confirming DTCs P0100, P0102 or P0103, use hand-held tester to check mass air flow ratio from the "DIAGNOSIS/ENHANCED OBD-II/DATA LIST/ALL DATA/MAF". See «MASS AIR FLOW RATIO»(ref-151771-S36389859902003080800000) table.
2. Read freeze frame data using hand-held tester or OBD-II scan tool, as freeze frame data records engine conditions when a malfunction is detected. When troubleshooting, it is useful to determine whether vehicle was running or stopped, engine was warmed up or not, air-fuel ratio was lean or rich, etc. at time of malfunction.

MASS AIR FLOW RATIO