Cylinder 11 Injector Circuit Low
The P0291 code means the vehicle's onboard diagnostic system has detected: Cylinder 11 Injector Circuit Low. This is a moderate severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $100 - $600 (wiring or connector at the low end; actuator/valve replacement at the high end)
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What Are the Symptoms of P0291?
- Check Engine Light on
- Drivability may be normal - many circuit faults show no symptom the driver notices
- The affected system may fall back to a default strategy, costing power or economy
- Related values implausible or frozen on a scan tool
What Causes P0291? (Most Likely First)
- Fault in the Cylinder 11 Injector circuit: the signal reading below its valid range - typically a short to ground or a failed component High
- Damaged wiring, a chafed harness, or a corroded connector at the Cylinder 11 Injector High
- Failed Cylinder 11 Injector Moderate
- Control module input/driver fault (rule this out last - it is the least common) Low
Can I Still Drive with P0291?
Yes, but fix soon. P0291 is rated moderate severity. It is not an immediate stop-driving fault, but it will not clear itself — book the repair rather than ignoring the light.
Frequently Asked Questions
What does P0291 mean?
P0291 is a generic OBD-II code defined by SAE J2012 as "Cylinder 11 Injector Circuit Low". It means the control module detected the signal reading below its valid range - typically a short to ground or a failed component
Can I keep driving with P0291?
Yes for normal use, but get it diagnosed - the system is running on a fallback strategy and a small wiring fault left alone tends to become a bigger one.
Does P0291 mean the same thing on every car?
Yes. P0291 is in the generic (SAE J2012) range, so the definition is standardized across manufacturers. The specific component location and repair procedure still vary by vehicle - check your service information.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P0291?
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Read the code and freeze-frame data, then watch the Cylinder 11 Injector live on a scan tool.
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Inspect the connector and harness at the Cylinder 11 Injector before replacing anything - wiring and corrosion cause most of these.
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Back-probe the circuit and compare signal, ground, and reference voltage against the service-manual values.
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Wiggle-test the harness while watching the live value if the fault is intermittent.
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Clear the code and confirm with a road test that covers the conditions in the freeze frame.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Which Vehicles Commonly Get P0291?
- All OBD-II vehicles - this is a generic (SAE J2012) code with the same meaning across makes
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