What it means
During cold start, the ECM detects that the injection pulse on cylinder 3 does not produce the expected combustion result. Cold-start specific pulse calibration deviates from learned values.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
During cold-start operation, the ECM compares cylinder 3's response to its injector command with its cold-start calibration and learned behavior. This code means cylinder 3's cold injection performance is outside the expected pattern, which may occur if its injector behaves differently at low temperature or fuel atomization is poor.
Common causes
Most likely first.
- Injector behaviour drifts at low temperature
- Poor fuel atomization at cold start
Symptoms
- Rough idle just after a cold start
- Engine stumble or vibration when cold
- Check-engine light
How to diagnose it
- Record freeze-frame and cylinder-specific misfire or contribution data at a cold startup to see whether cylinder 3 is the main deviation.
- Check whether the rough idle or stumble occurs only before the engine warms and whether it clears afterward.
- Inspect cylinder 3's injector connector and wiring for corrosion, looseness, chafing, or damage.
- Compare cylinder 3's injector command and contribution with the other cylinders in live data during cold operation.
- If cylinder 3 remains abnormal, have its injector flow and spray evaluated under relevant conditions against the manufacturer's specification.
Common fixes
- Refuel with the vehicle's specified fuel if fuel quality is suspect and monitor subsequent cold starts.
- Repair a loose or damaged cylinder 3 injector connector or harness.
- Clean or service the cylinder 3 injector if deposits are confirmed and it can be serviced.
- Replace the cylinder 3 injector if testing finds cold-start performance outside the manufacturer's specification.
Can I keep driving?
If the engine runs acceptably once warm and the warning light is steady, avoid high loads during cold starts and arrange diagnosis, since repeated poor combustion raises emissions. Stop driving if the light flashes or the engine shakes, stalls, or loses power severely.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.