System: Powertrain (P-Code)
SAE Standard (Generic)
Family: ECT Sensor Circuit
Code P0118: Engine Coolant Temperature Sensor 1 Circuit High
Diagnostic & Technical Explanation
Code P0118 (Engine Coolant Temperature Sensor 1 Circuit High) sets when the ECM sees an open, shorted, or implausible resistance from an engine or radiator coolant temperature sensor, or a correlation mismatch between redundant coolant/oil/ambient temperature signals. Causes are a corroded connector, a failed thermistor element, low coolant exposing the sensor tip, or chafed wiring.
First-listed procedure
Rank #1
Top off coolant and inspect ECT sensor connector
Easy DIY
This is the first procedure in the authored
consideration order, not a measured cause likelihood. Execute it only when its prerequisites
and diagnostic findings support it. Its cost and labor estimates (where known), the step-by-step procedure and the
remaining 2 procedure(s) are in the licensed dataset. Ordering context.
Full family: ECT Sensor Circuit
What this page does not show
This page publishes the fault mechanism and the code index. The licensed dataset adds, for
every one of the 15,886 codes, the full authored repair set (56,729 procedures in total)
with the fields deliberately withheld here:
- Procedures 2..n after the first-listed procedure
- Aftermarket parts cost ranges in USD (
est_parts_cost_min/max_usd)
- Professional labor-hour estimates (
est_labor_hours)
- Step-by-step diagnostic and repair instructions
- Replacement-part mappings and catalog lookups
- 6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)