P1311

Code

DAEWOO P — Powertrain

IG. COIL 1 - OVER OUTPUT

Brand: DAEWOO

Type: P — Powertrain

Views: UK: 1 EN: 7 RU: 2

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Page language: EN

Causes

Faulty ignition coil (internal short, degraded insulation or internal wiring failure)
Short or intermittent short in the coil primary wiring to battery voltage (B+) or to the ECM driver
Open or high-resistance ground for the coil circuit
Faulty ECM/ignition driver transistor or control circuit
Corroded or damaged coil connector, pins or wiring harness
Aftermarket or incorrect coil with different electrical characteristics

Symptoms

Check Engine Light (MIL) illuminated
Engine misfire on cylinder 1, rough idle or hesitation
Reduced engine power and acceleration
Poor fuel economy
Hard starting or occasional no-start
Backfiring or increased ignition noise

What to check

Read freeze frame and live data with a scan tool; note misfire counters and coil driver status
Visual inspection of coil, connector, wiring harness and engine grounds for damage or corrosion
Check supply voltage at coil B+ and verify good chassis/engine ground
Inspect coil connector pins for corrosion, bent pins or pushed-out terminals
Measure coil primary and secondary resistance and compare to spec (service manual)
Swap coil 1 with another cylinder's coil (if coils are identical) and see if code follows the coil

Signal parameters

Primary coil resistance (typical range): ~0.3–2.0 ohms (consult vehicle service manual for exact spec)
Secondary coil resistance (typical range): ~5 kΩ–15 kΩ (manufacturer-specific)
Supply (B+) to coil: ~12 V with ignition on; should be stable
Driver switching: PWM or ground-switch pulses; dwell typically a few milliseconds (varies by engine load/ECM)
Primary current when charging: several amps peak (varies); excessive current or voltage spikes indicate fault
Expected waveform: clean repeatable primary charge/discharge pulses; excessive amplitude, noise or stuck-on state indicates problem

Diagnostic algorithm

Connect an advanced scan tool and record freeze frame/live data. Note whether P1311 is confirmed or pending and any concurrent misfire codes (e.g., P0301).
Perform a thorough visual inspection: coil, boot, connector, wiring harness routing, and engine grounds. Repair obvious damage or corrosion.
Verify battery voltage at coil B+ with ignition on. Check for a solid ground at coil mounting/engine ground.
Unplug coil 1 connector, inspect pins and connector housing. Clean or repair terminals as needed.
Measure primary and secondary resistances of coil 1 and compare to service values. If out of spec, replace the coil.
If coil resistance is normal, swap coil 1 with a known-good coil from another cylinder (if coils are identical). Clear codes and run engine to see if the fault follows the coil.
Back-probe the coil driver circuit with an oscilloscope while cranking/running: check for correct switching waveform, dwell, and absence of excessive voltage spikes or a driver stuck in on/off state.
Use a clamp meter or shunt to check primary current if needed; look for abnormally high current draw.
If wiring/coil checks pass but the driver waveform is abnormal or open/short to B+ is present at the driver output, inspect wiring to the ECM and corresponding pins. Repair any harness faults.
If wiring and coil are confirmed good and problem persists, test/replace the ECM only after verifying all other components. Follow manufacturer service procedures before ECM replacement.
After repairs, clear codes and perform a road test and re-check for recurrence. Confirm no additional DTCs or misfires.

Likely causes

Damaged or failing ignition coil on cylinder 1
Wiring short to battery or intermittent short in coil primary circuit
Corroded connector or poor ground at the coil
Faulty ECM driver (after all wiring and coil ruled out)

Fault status

⚠️ Status

Ignition coil 1 circuit over-output detected — ECM has detected abnormal/high output behavior from the cylinder 1 ignition coil driver. Inspect coil, wiring and ECM driver circuit.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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P1311 — IG. COIL 1 - OVER OUTPUT