CorollaFix

P0100 (blink 31, 1ZZ) on Toyota Corolla E120: MASS AIR FLOW CIRCUIT MALFUNCTION

Short answer: P0100 means “MASS AIR FLOW CIRCUIT MALFUNCTION”. The car’s computer has found a fault in the EFI 1ZZ-FE system and turns on the Malfunction indicator lamp (Check Engine). First check: workshop check order (RM821E): READ VALUE OF MAF/AFM -> INSPECT INTAKE AIR FLOW METER SUB−ASS(POWER SOUCE VOLTAGE) -> INSPECT ECU -> CHECK HARNESS AND CONNECTOR(ENGINE ECU−AIR FLOW METER) -> CHECK HARNESS AND CONNECTOR(AIR FLOW METER +B CIRCUIT) -> INSPECT INTAKE AIR FLOW METER SUB−ASS(POWER SOURCE VOLTAGE).

Code
P0100 · blink 31
System
EFI 1ZZ-FE
Dashboard light
Malfunction indicator lamp (Check Engine)
Applies to
1ZZ-FE 1.8 (PK Altis 2005-08 ZZE122; JDM ZZE122/124, Allex/Runx/Fielder 1.8)
Confidence
high (official Toyota RM821E)
Source
toyotamanuals.gitlab.io

Symptoms and when it is set

  1. Open or short in air flow meter circuit with more than 3 sec. engine speed less than 4,000 rpm

Likely causes

  1. Open or short in air flow meter circuit; Air flow meter; Engine ECU

What to check, in order

  1. Workshop check order (RM821E): READ VALUE OF MAF/AFM -> INSPECT INTAKE AIR FLOW METER SUB−ASS(POWER SOUCE VOLTAGE) -> INSPECT ECU -> CHECK HARNESS AND CONNECTOR(ENGINE ECU−AIR FLOW METER) -> CHECK HARNESS AND CONNECTOR(AIR FLOW METER +B CIRCUIT) -> INSPECT INTAKE AIR FLOW METER SUB−ASS(POWER SOURCE VOLTAGE)

Related on this car

Same code on other cars

← P1656/39 P0110/24 →

Clearing the code does not fix the fault. If it comes back, the problem is still there. For brakes, airbags and steering, see a trained mechanic.