P2C5D

Code

Generic P — Powertrain

Cylinder 6 Fuel Injector B Offset Learning At Max Limit

Brand: Generic

Type: P — Powertrain

Views: UK: 27 EN: 45 RU: 20

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Faulty or clogged fuel injector (Cylinder 6, Injector B)
Injector driver fault in PCM/ECM
Open, shorted or high-resistance wiring or connector to injector
Poor ground or power supply to injector circuit
Low fuel rail pressure or unstable fuel pump
Faulty mass Air Flow (MAF) or MAP sensor affecting trims

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Rough idle, vibration or shaking at idle
Reduced engine performance or hesitation under load
Poor fuel economy
Possible misfire codes (cylinder 6 related) or degraded emissions
Hard starting or extended cranking in some cases

What to check

Read freeze frame and freeze data related to P2C5D
Scan live data: learned injector offsets, short/long term fuel trims, commanded injector pulse widths
Check for related codes (misfire, injector circuit, fuel pressure, O2 sensor)
Visual inspection of injector connector, wiring, and PCM grounds/power
Measure injector resistance and compare to specification
Backprobe injector connector to verify pulse and ground when cranking/running (noid light or oscilloscope)

Signal parameters

Injector pulse width (ms) commanded vs actual
Learned injector offset (adaptive trim) value for Cylinder 6 Injector B
Short-term and long-term fuel trim (STFT/LTFT)
O2/AFR sensor voltages or wideband lambda
Fuel rail pressure (psi/bar)
Injector coil resistance (ohms)

Diagnostic algorithm

Retrieve all stored and pending codes and freeze frame data; record learned offset and fuel trim values for cylinder 6.
Visually inspect injector harness and connector for corrosion, damage or loose pins. Repair any issues found.
With ignition off, measure injector coil resistance at the connector and compare to spec. Replace if out of range.
Backprobe injector connector with a noid light or oscilloscope while cranking/running to confirm injector drive pulse and proper ground switching.
Check supply voltage and ground at injector connector with engine off and while cranking. Repair poor supply/ground.
Check fuel rail pressure and the fuel delivery system; repair if pressure is low or unstable.
Swap the suspect injector with another cylinder (if practical) and clear codes. If the learned-offset fault moves to the other cylinder, the injector is likely faulty.
If swapping does not move the fault, suspect wiring or PCM driver. Perform continuity/resistance tests on injector circuit to PCM and check for shorts to power or ground.
Perform a cylinder contribution/balance test and compression or leak-down test on cylinder 6 to rule out mechanical issues.
Inspect O2/AFR sensors and MAF/MAP sensors operation; bad sensors can drive incorrect adaptations. Replace or service as required.
After repairs, clear codes and perform drive cycle or relearn procedure per manufacturer to allow adaptive offsets to re-establish. Re-check for re-occurrence.

Likely causes

Injector B on cylinder 6 is clogged or leaking, causing persistent required offset
Wiring fault (intermittent open/short) at the injector connector or harness
PCM/ECM injector driver channel degraded
Fuel pressure too low or erratic, causing improper injection and learned offset
Cylinder 6 has mechanical loss (low compression) causing the adaptive system to max out

Fault status

⚠️ Status

Adaptive fuel offset for Cylinder 6, Injector B reached maximum learning limit. ECM can’t further compensate for the imbalance—inspection of injector, circuit, fuel delivery, sensors, and cylinder condition is required. MIL will be set.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours