P0505 (blink 33) on Toyota Corolla E120: IDLE CONTROL SYSTEM MALFUNCTION
Short answer: P0505 means “IDLE CONTROL SYSTEM MALFUNCTION”. The car’s computer has found a fault in the EFI 1NZ-FE/2NZ-FE system and turns on the Malfunction indicator lamp (Check Engine). First check: workshop check order (RM821E): CHECK HARNESS AND CONNECTOR -> CHECK HARNESS AND CONNECTOR(RSD CIRCUIT) -> INSPECT THLOTTLE BODY IDLE SPEED CONTROL VALVE ASSY -> CHECK HARNESS AND CONNECTOR(CHECK FOR OPEN AND SHORT BETWEEN.
- Code
- P0505 · blink 33
- System
- EFI 1NZ-FE/2NZ-FE
- Dashboard light
- Malfunction indicator lamp (Check Engine)
- Applies to
- 2NZ-FE 1.3 (PK XLi/GLi NZE120) and 1NZ-FE 1.5 (JDM NZE121/NZE124 Corolla/Fielder/Runx)
- Confidence
- high (official Toyota RM821E)
- Source
- toyotamanuals.gitlab.io
Symptoms and when it is set
- Idle speed continues to vary greatly from target speed (2 trip detection logic)
Likely causes
- Open or short in ISC valve circuit; ISC valve; Engine ECU
What to check, in order
- Workshop check order (RM821E): CHECK HARNESS AND CONNECTOR -> CHECK HARNESS AND CONNECTOR(RSD CIRCUIT) -> INSPECT THLOTTLE BODY IDLE SPEED CONTROL VALVE ASSY -> CHECK HARNESS AND CONNECTOR(CHECK FOR OPEN AND SHORT BETWEEN
Related on this car
- Idle hunting / stalling when the clutch is pressed (IACV/throttle body)
- All fault codes for this car
- Warning lights
- Where the parts are (parts map)
- Common problems
Same code on other cars
- P0505 · Toyota Passo (1st gen)
- P0505 · Toyota Vitz (1st gen)
- P0505 · Toyota Corolla (11th gen, E170)
- P0505 · Toyota Corolla (10th gen, E140)
- P0505 · Honda City (5th gen, GM2)
- P0505 · Honda Civic (10th gen, FC)
- P0505 · Suzuki Wagon R (Pakistan, K10B)
- P0505 on all cars compared
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.

