Code
P0281
GWM
P — Powertrain
- 7 cylinder is incorrectly balanced
AI status
Completed
Completed
100%
Causes
- Ignition system fault on cylinder 7 (coil, spark plug, wiring, connector)
- Fuel injector fault for cylinder 7 (sticking, clogged, electrical)
- Low compression or mechanical damage in cylinder 7 (worn rings, valve, head gasket)
- Timing/timing-chain/camshaft/crankshaft correlation error affecting cylinder 7
- Intake/exhaust leak or EGR issue affecting that cylinder
- Fuel delivery or pressure problems, contaminated fuel
Symptoms
- Check Engine / MIL illuminated
- Engine rough idle or vibration, especially at idle or low load
- Poor acceleration and reduced engine power
- Increased fuel consumption
- Intermittent or consistent misfire felt or recorded on cylinder 7
- Possible white/blue/black exhaust smoke depending on cause
What to check
- Read stored DTCs and freeze frame data; note misfire counts and conditions
- Inspect wiring and connectors for injector and ignition coil at cylinder 7 for corrosion, damage, or poor contact
- Swap coil/plug or injector with another cylinder to see if imbalance moves
- Measure fuel rail pressure to confirm adequate fuel supply
- Perform cylinder compression and/or leak-down test on cylinder 7 and compare to others
- Check cam and crank timing alignment and timing chain/belt condition
Signal parameters
- Misfire counter for cylinder 7: >0 events (variable by vehicle)
- Relative compression: cylinder 7 compression significantly lower than average (typical pass if within ~10-15% of other cylinders)
- Short-term fuel trim (STFT) for relevant bank/cylinder: abnormal positive/negative deviation
- Long-term fuel trim (LTFT): sustained offset indicates fueling or air leak
- Injector pulse width for cylinder 7: compares to identical cylinder under same conditions
- Ignition coil primary/secondary waveform: missing or weak spark on cylinder 7
Diagnostic algorithm
- Confirm code and capture freeze-frame / live data (misfire counts, RPM, load, temp).
- Visual inspection: wiring, connectors, boots, and fuel injector harness at cylinder 7.
- Swap coil and/or spark plug from cylinder 7 with another cylinder; clear codes and run to see if imbalance follows the component.
- Swap injector with another cylinder (if practical) and retest to isolate injector vs mechanical.
- Perform a compression test on all cylinders; if cylinder 7 low, follow with a leak-down test to identify valve/piston/head gasket issues.
- Check fuel rail pressure and injector pulse width using a scan tool; verify injector electrical continuity/resistance against spec.
- Capture ignition coil and injector waveforms with an oscilloscope (or lab scope tool) to identify intermittent or weak signals.
- Verify cam/crank timing and sensor sync; check for timing chain/belt stretch or jumped tooth that could affect one cylinder.
- Inspect intake/exhaust for leaks and EGR function; repair as required.
- Repair or replace the defective component (injector, coil, plug, wiring, gasket, timing component), clear codes and perform road test and re-scan to confirm the issue is resolved.
- Note: If tests are inconclusive, consider ECU/sensor faults and consult manufacturer service information.
Likely causes
- Faulty or intermittent injector for cylinder 7
- Bad ignition coil or spark plug on cylinder 7
- Low compression at cylinder 7 (valve seating, piston rings, head gasket)
- Wiring harness/connector damage to injector or ignition circuit of cylinder 7
- Cam/crank timing drift causing that cylinder to fire out of sequence
Fault status
Status
Cylinder 7 imbalance detected — ECU recorded uneven contribution for cylinder 7 (misfire/imbalance condition). Further diagnosis required to identify cause.
Repair difficulty: Medium
Diagnostic time: 1.5 - 3.0 hours
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