Code
P1323
DAEWOO
P — Powertrain
IG. COIL 4 - OVER OUTPUT
Views:
UK: 1
EN: 4
RU: 0
AI status
Completed
Completed
100%
Causes
- Shorted ignition coil primary winding
- Short to battery in coil 4 wiring or connector
- Short to ground in coil 4 wiring
- Corroded/loose coil connector or poor pin contact
- Damaged harness (chafing, pinched, melted insulation)
- Faulty ignition coil (internal short or breakdown)
Symptoms
- Check Engine Light (MIL) illuminated
- Misfire or rough running on cylinder 4
- Loss of power, hesitation or poor acceleration
- Increased fuel consumption
- Possible hard start or no-start if condition is severe
- Intermittent misfire or MIL depending on wiring/connector condition
What to check
- Read and record freeze frame data and stored/active DTCs with a scan tool
- Check for additional related codes (misfire, coil circuit codes)
- Visual inspection of coil 4, connector and nearby wiring for damage, corrosion, heat damage or oil intrusion
- Wiggle test: start engine and wiggle harness/connectors to see if fault triggers
- Inspect fuses and power supply feeding ignition coils
- Swap coil 4 with another cylinder’s coil and see if code follows coil (engine off, ignition disabled)
Signal parameters
- Coil primary resistance (ohms) — expected value per OEM spec
- Coil secondary resistance (ohms) — expected value per OEM spec
- Battery voltage at coil connector (V)
- ECM coil driver command (on/off or duty cycle)
- Coil driver voltage/current during dwell (V, A)
- Dwell time (ms) commanded vs actual
Diagnostic algorithm
- Retrieve all stored codes and freeze frame data; record engine conditions when fault set.
- Perform a thorough visual inspection of coil #4, connector, and wiring harness for damage, corrosion, oil, or signs of heat damage. Repair visible wiring/connector issues.
- With ignition off, unplug coil #4 and inspect terminals. Check for corrosion, bent pins, or contamination; clean/repair as needed.
- Measure coil #4 primary and secondary resistance and compare to OEM specifications. If out of spec, replace coil.
- Swap coil #4 with another cylinder’s coil (keep connectors and harness in place) then clear codes and run the engine. If the code/misfire follows the coil, replace the coil.
- If the code remains on cylinder 4 after coil swap, perform wiring checks: verify continuity from coil connector to ECM, check for short to battery or ground, and check supply/ground voltages with respect to battery.
- Use an oscilloscope to inspect the primary waveform and driver behavior at coil #4 while cranking/running. Look for abnormal amplitude, noise, or excessive current draw. If scope not available, a current clamp during cranking can indicate excessive current.
- If wiring and coil test good but over‑output persists, suspect a damaged ECM driver. Confirm with bench/ECM diagnostics per manufacturer procedures before replacing ECM.
- After repair, clear codes and road test to verify the fault does not return. Re-inspect if intermittent recurrence occurs.
Likely causes
- Shorted or internally failed ignition coil #4
- Wiring short (power or ground) at coil #4 connector
- Poor connector/terminal contact at coil #4
- ECM ignition driver transistor failure
Fault status
Status
P1323 — Ignition Coil 4 Over Output. ECM detected excessive output (current/voltage) from the ignition coil driver circuit for cylinder 4; possible shorted coil, wiring short, connector fault, or defective ECM driver.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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