P0270

Cylinder 4 Injector A Circuit Low

Injector circuit Generic OBD-II High

What it means

P0270 means the ECM detects an abnormally low signal on the cylinder 4 injector control circuit. If that injector isn't firing properly, cylinder 4 misfires — causing a rough idle, reduced power, and, over time, possible catalytic-converter damage until the wiring or injector is repaired.

High

Can I keep driving? Usually driveable, but cylinder 4 may misfire and run rough; sustained misfiring can overheat the catalytic converter, so fix it soon.

Real-world scan data

Seen in

286

scans in the past year

Found in

0.1%

of scans

0.1%

of scans that found faults

Appears alongside · share of P0270 scans

P0261in 60.5% of scans

P0267in 57.7% of scans

P0264in 57.3% 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
Rough idle or a misfire on cylinder 4
Reduced power and hesitation
Possible dead cylinder and increased fuel use

Common causes

Most likely first

Damaged wiring or a corroded connector at the cylinder 4 injectorLikely
Faulty cylinder 4 fuel injector (open or shorted winding)Common
Poor ground or open in the injector control circuitCommon
PCM injector-driver fault (less common)Less often

How to diagnose & fix

Work through it in order

Read freeze-frame data and inspect the cylinder 4 injector connector and wiring.
Measure the injector's resistance and compare it to the other injectors.
Check the injector control-circuit voltage and ground from the connector.
Replace the injector if it's out of spec; consider the PCM driver only after wiring is confirmed good. Clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0270?+

Short-term yes, but a dead or misfiring cylinder makes the engine run rough and can damage the catalytic converter over time. Repair it soon.

Can I just clear P0270?+

It returns until the injector or its wiring is fixed. A 'circuit low' code reflects a real electrical fault on that injector.

Read & clear P0270 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