P2C5C

Code

Generic P — Powertrain

Cylinder 6 Fuel Injector B Offset Learning At Min Limit

Brand: Generic

Type: P — Powertrain

Views: UK: 17 EN: 28 RU: 26

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Page language: EN

Causes

Faulty or leaking fuel injector on cylinder 6
Shorted or low-resistance injector driver circuit
Open or intermittent injector wiring/connector
Fuel pressure too high or regulator fault
Intake air leak or other mechanical issue affecting cylinder 6
Mass airflow (MAF) or fuel metering sensors providing incorrect data

Symptoms

Check Engine Light (MIL) on
Misfire or rough running at idle, possibly stored P0306
Poor fuel economy
Reduced power or hesitation under load
Elevated tailpipe emissions/smoke (rich condition)

What to check

Read freeze frame and live data: injector offset/learning value for cylinder 6, short/long‑term fuel trim, misfire counts
Inspect injector connector and wiring for damage, corrosion, or pin push‑out
Measure injector resistance (ohms) and compare to specification
Monitor injector pulse width and commanded duty cycle with a scan tool or oscilloscope
Check fuel rail pressure at idle and during cranking
Perform a cylinder balance or cylinder contribution test

Signal parameters

Injector pulse width (ms) — expected varying with load/idle
Injector driver voltage (V) and current (A) during pulse
Injector coil resistance (Ω) — compare to spec
Fuel rail pressure (kPa or psi) — steady and within spec
Short-term and long-term fuel trim (%)
Cylinder 6 misfire count or balance contribution (%)

Diagnostic algorithm

Retrieve freeze frame and live data; record injector offset/learning value for cylinder 6 and related fuel trims/misfire data.
Visually inspect the injector, connector, and wiring for damage, corrosion, or disconnection. Wiggle test while monitoring for changes.
With ignition off, measure static injector resistance; compare to OEM spec. Significant deviation suggests faulty injector.
Relieve fuel pressure per safety procedure before removing components. Check fuel rail pressure at key-on/idle to rule out overpressure.
Use a lab scope or noid light to confirm injector drive pulse presence and shape while engine is running; verify driver is not held on.
Perform a cylinder balance or disable-spark test to see if removing injector function changes rpm as expected. If problem follows injector, suspect injector or wiring.
Swap injector (or injector harness) between cylinder 6 and another cylinder. If the learned offset or misfire moves to the new cylinder, replace the injector/harness accordingly.
If wiring swap does not move the fault, suspect ECM driver fault or calibration; check other sensors (MAF, fuel pressure sensor, cam/crank) that affect fueling.
After repairs, clear codes and perform a road/test run to allow the ECM to relearn offsets; verify that learn values are within range and code does not return.
If intermittent or no fault found, obtain manufacturer service information for specific learning limits and consider ECM reflash or replacement as last resort.

Likely causes

Leaking or stuck-open injector on cylinder 6
Injector driver stuck-on/short to battery in wiring or ECU output for cylinder 6
High fuel rail pressure
Wiring/connectors corrosion or intermittent connection at injector
Sensor input (MAF, crank/cam) causing incorrect fueling and forcing offset to limit

Fault status

⚠️ Status

Cylinder 6 fuel injector offset learning reached minimum limit — ECM cannot reduce injector contribution further; check injector, wiring, fuel pressure, and related sensors.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1-3 hours