Code
P0280
GWM
P — Powertrain
- High-performance chain injector 7 cylinder
AI status
Completed
Completed
100%
Causes
- Open or short in injector wiring harness to cylinder 7
- Corroded or loose injector connector or terminal
- Failed injector (internal short or open winding)
- Faulty injector driver in the engine control module (ECM)
- Blown fuse or faulty power feed/relay to injectors
- Poor ground at engine or chassis
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
- Rough idle or vibration
- Cylinder 7 misfire or reduced power
- Poor fuel economy
- Intermittent faults that may return after cleaning or tapping connector
- Difficulty starting or increased smoke (diesel engines)
What to check
- Read freeze‑frame and live data with a scan tool; note injector command and any misfire counts
- Visually inspect injector connector, wiring harness, and nearby components for damage, corrosion, or rubbing
- Check related fuses and injector power/relay operation
- Measure injector coil resistance at the connector and compare to manufacturer specification
- Backprobe connector while cranking to confirm injector supply voltage and driver switching
- Use an oscilloscope or noid light to verify injector pulse waveform and pulse width
Signal parameters
- Injector coil resistance: consult GWM spec — typical ranges: low‑impedance injectors ~2–4 Ω, high‑impedance injectors ~12–16 Ω. Verify against vehicle specification.
- Supply voltage to injector: nominal battery voltage (~11–14 V) present at the power feed pin with ignition ON
- Driver output: switching to ground (0 V) when commanded; when OFF it should be near battery voltage
- Pulse width: varies with load/engine speed; idle pulses commonly 1–5 ms (use scanner/live data for expected values)
- Oscilloscope waveform: clean square pulses; look for missing pulses, slow edges (high resistance), or noise indicating short/open
Diagnostic algorithm
- Retrieve full fault data with a scan tool, record freeze‑frame, clear code, and attempt to re‑reproduce.
- Visually inspect injector 7 connector and wiring route for damage, corrosion, or exposure to heat. Repair visible damage.
- With ignition OFF, disconnect injector 7 and measure coil resistance between its terminals. Compare to spec. Replace if out of range.
- Reconnect and backprobe connector. With key ON or engine cranking, confirm constant 12 V supply to the injector power pin and that the driver pin toggles to ground when the injector is commanded.
- Use an oscilloscope or noid light while commanding injector 7 to verify pulse presence, shape, and width. Note any weak/absent pulses or abnormal waveforms.
- Perform a wiggle test on harness/connectors while monitoring live data or waveform to find intermittent faults.
- Swap injector 7 with another known good injector (same spec). If fault follows the injector, replace the injector. If fault remains on cylinder 7, focus on wiring/ECU.
- Inspect and test fuse(s), relay(s), and common power/ground circuits for the injector bank. Repair or replace as needed.
- If wiring and injector check good, test the ECU driver output for shorts/opens and consult manufacturer procedures before replacing ECU. Consider professional ECU bench test or replacement only after exhausting wiring/injector possibilities.
- After repair, erase codes and road test to confirm no reappearance; recheck live data and misfire counts.
Likely causes
- Damaged wiring or chafed insulation near the injector rail
- Corroded pin or connector causing high resistance or intermittent contact
- Injector coil open or shorted (internal failure)
- ECU driver transistor degraded or shorted to ground/voltage
- Lost 12 V supply or injector power rail fuse/relay fault
Fault status
Status
Injector circuit fault detected for high‑performance injector at cylinder 7. Possible open, short, high resistance, intermittent connection, or ECU driver failure. Further electrical testing required.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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