CorollaFix

P0115 (blink 22) 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 1NZ-FE/2NZ-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 ECU(CHECK FOR SHORT) -> INSPECT ECU(ENGINE ECU CONNECTOR) -> CHECK WATER TEMPERATURE SENSOR -> CHECK HARNESS AND CONNECTOR (OPEN AND SHORT BETWEEN THE TERMI-.

Code
P0115 · blink 22
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

  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 ECU(CHECK FOR SHORT) -> INSPECT ECU(ENGINE ECU CONNECTOR) -> CHECK WATER TEMPERATURE SENSOR -> CHECK HARNESS AND CONNECTOR (OPEN AND SHORT BETWEEN THE TERMI-

Related on this car

Same code on other cars

← 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.