What it means
The engine control module detects voltage below the expected range in the cylinder 5 injector circuit. It sets the code when the circuit remains low during injector operation under the conditions monitored by the vehicle calibration.
How it works
The engine control module controls the fuel injector circuit for cylinder 5 so fuel is delivered to that cylinder at the right time. P0273 indicates the circuit signal is below the expected level, which can be caused by a short to ground, damaged wiring, a poor connection, or a failed injector.
Common causes
Most likely first.
- Short to ground in injector wiring
- Faulty cylinder 5 injector
- Loose or corroded injector connector
- Open or damaged wiring
- Engine control module driver fault
Symptoms
- Rough idle or misfire
- Reduced power
- Poor fuel economy
- Check engine light
How to diagnose it
- Record freeze-frame data and check cylinder 5 misfire counts and live engine data to see whether the fault coincides with rough running.
- With the ignition off, inspect the cylinder 5 injector connector and harness for corrosion, looseness, chafing, or damage.
- Check the cylinder 5 injector circuit for a short to ground or an open using the vehicle wiring diagram and manufacturer's procedure.
- Test the cylinder 5 injector winding and compare it with the manufacturer's specification.
- If the injector and wiring test correctly, check the control module driver and connector before considering module repair.
Common fixes
- Clean and secure the cylinder 5 injector connector or repair corroded pins.
- Repair a cylinder 5 injector wire that is shorted to ground, open, or damaged.
- Replace the cylinder 5 injector if it fails the manufacturer's electrical test.
- Repair the control module driver only after the injector circuit has passed testing.
Can I keep driving?
If the engine is misfiring, avoid hard acceleration and extended driving because unburned fuel can damage the catalytic converter. Stop if shaking is severe or power loss makes it unsafe to continue.
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.