P0115 (blink 22, 1ZZ) on Toyota Corolla E120: WATER TEMP. CIRCUIT MALFUNCTION

Short answer: P0115 means “WATER TEMP. 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 COOLANT TEMP/WATER TEMP -> CHECK HARNESS AND CONNECTOR(CHECK FOR OPEN) -> INSPECT ECU(CHECK FOR OPEN) -> CHECK HARNESS AND CONNECTOR(CHECK FOR SHORT) -> INSPECT ENGINE ECU FUNCTION(CHECK FOR SHORT) -> INSPECT ENGINE ECU FUNCTION(ENGINE ECU CONNECTOR) -> CHECK WATER TEMPERATURE SENSOR -> CHECK HARNESS AND CONNECTOR(ENGINE ECU−WATER TEMPERATURE.

Code

P0115 · blink 22

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 water temp. sensor circuit

Likely causes

1. Open or short in water temp. sensor circuit; Water temp. sensor; Engine ECU

What to check, in order

1. Workshop check order (RM821E): READ VALUE OF COOLANT TEMP/WATER TEMP -> CHECK HARNESS AND CONNECTOR(CHECK FOR OPEN) -> INSPECT ECU(CHECK FOR OPEN) -> CHECK HARNESS AND CONNECTOR(CHECK FOR SHORT) -> INSPECT ENGINE ECU FUNCTION(CHECK FOR SHORT) -> INSPECT ENGINE ECU FUNCTION(ENGINE ECU CONNECTOR) -> CHECK WATER TEMPERATURE SENSOR -> CHECK HARNESS AND CONNECTOR(ENGINE ECU−WATER TEMPERATURE

Related on this car

• Water pump leak
• Overheating on the motorway / fan not running
• All fault codes for this car
• Warning lights
• Where the parts are (parts map)
• Common problems

Same code on other cars

• P0115 · Toyota Passo (1st gen)
• P0115 · Toyota Vitz (1st gen)
• P0115 · Toyota Corolla (11th gen, E170)
• P0115 · Toyota Corolla (10th gen, E140)
• P0115 · Honda City (5th gen, GM2)
• P0115 · Honda Civic (10th gen, FC)
• P0115 · Suzuki Wagon R (Pakistan, K10B)
• P0115 on all cars compared

← P0110/24 P0120/41 →

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.