P0119

Engine Coolant Temperature Sensor 1 Circuit Intermittent/Erratic

Cooling / temperature sensor Generic OBD-II High

What it means

P0119 means the engine coolant temperature sensor signal is cutting out or jumping around instead of changing smoothly. The ECM relies on this reading for cold-start enrichment, cooling-fan control, and closed-loop fueling, so an erratic signal can cause hard cold starts, rich running, and fan quirks. It's almost always an intermittent wiring or connector fault or a failing sensor.

High

Can I keep driving? Usually drivable, but an erratic coolant signal can trigger hard cold starts, rich running, and cooling-fan quirks — fix it soon and watch the temperature gauge.

Real-world scan data

Seen in

499

scans in the past year

Found in

0.1%

of scans

0.1%

of scans that found faults

Appears alongside · share of P0119 scans

P0118in 55.7% of scans

P0115in 35.5% of scans

P1646in 16.6% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Hard cold starts or rough running until warm
Cooling fans cycling at the wrong times
Poor fuel economy
Fluctuating or implausible temperature readings

Common causes

Most likely first

Faulty engine coolant temperature (ECT) sensorLikely
Intermittent open or short in the sensor wiringCommon
Loose or corroded sensor connectorCommon
Rarely, an ECM/PCM faultLess often

How to diagnose & fix

Work through it in order

Wiggle-test the ECT connector and harness while watching live data for the reading to jump or drop out.
Inspect the connector for corrosion or spread pins and reseat it.
Measure sensor resistance as the engine warms; it should change smoothly. Replace it if the reading is erratic.
If wiring and sensor are good, suspect the ECM. Clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0119?+

Short trips are usually fine, but because the coolant sensor affects fueling and fan control, fix it promptly and stop if the engine shows signs of overheating.

Can I just clear P0119?+

You can, but an intermittent fault like this comes back; the real fix is tracking down the loose connection or replacing the sensor.

Read & clear P0119 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX