Code
P1348
DAEWOO
P — Powertrain
#8 ION CIRCUIT
Views:
UK: 2
EN: 7
RU: 5
AI status
Completed
Completed
100%
Causes
- Open or shorted ION wiring for cylinder #8
- Corroded, loose or damaged connector at the #8 coil/ION harness
- Failed ignition coil or ignition module serving cylinder #8
- Contaminated or water-damaged connector or sensor
- High resistance in wiring (intermittent connection)
- Faulty ECM/PCM ion input circuit (less common)
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Possible misfire on cylinder #8 or general rough idle
- Reduced engine power, hesitation, or poor throttle response
- Reduced fuel economy
- Misfire-related drivability complaints under load or during acceleration
What to check
- Read and record freeze-frame and all stored DTCs; note related misfire or ignition codes
- Visual inspection of the #8 ignition coil, connector, and wiring loom for damage, corrosion, or pins pushed out
- Check for moisture, oil, burnt pins, or corrosion in the coil/connector and at the ECM connector
- Check related fuses and power/ground circuits for the ignition coils and ECM
- Backprobe the coil/ION connector while cranking to observe presence of expected reference signals (use proper test equipment)
- Swap the #8 coil with another known-good coil (if coils are identical) and see if the DTC follows the coil or stays with cylinder #8
Signal parameters
- Signal type: ion/ionization detection pulses synchronized with ignition events (timing depends on engine speed)
- Expected behavior: brief pulses or changes in current/voltage on the ION line each combustion event; missing or constant signal indicates a fault
- Voltage/amplitude: system-dependent; may be low-voltage current/voltage pulses rather than full 12 V switched signals
- Timing: pulse occurrence should match ignition timing/number of combustion events per revolution; frequency increases with engine speed
Diagnostic algorithm
- Retrieve all DTCs and freeze-frame data. Note if misfire codes (e.g., P0308) or coil circuit codes are present. Clear codes after recording. 2. Perform visual inspection: check the #8 coil, connector, wiring harness, and ECM connector for damage, corrosion, or loose pins. Repair obvious issues. 3. With ignition off, disconnect the coil connector and inspect terminals for corrosion or damage. Repair or replace connector as needed. 4. Check for proper power and ground to the ignition coil module using a digital multimeter (refer to vehicle wiring). If power/ground missing, trace and repair. 5. Swap the #8 coil with a known-good coil from another cylinder and clear codes. Crank/run engine. If the code moves to the other cylinder, replace the coil. 6. Backprobe the ION signal wire at the coil while cranking/idle using an oscilloscope (preferred) or high-speed graphing tool to confirm presence and shape of ion pulses. Compare to a good cylinder or known-good waveform. 7. Measure continuity and resistance between the coil’s ION pin and the ECM ION input pin; repair wiring if open/high resistance or short to ground/12 V is found. 8. If wiring, connector, and coil check okay, consider ECM input circuit fault. Confirm with bench diagnostics or compare to other ECM channels. Replace ECM only after eliminating wiring/coil faults. 9. After repair, clear codes and road-test to confirm the fault does not return and drivability is restored.
Likely causes
- Damaged or chafed harness to the #8 coil/ION pin
- Failed ignition coil or integrated igniter on cylinder #8
- Corroded or pushed-out connector at the coil or ECM
- Short to chassis ground or to battery voltage in the ION lead
Fault status
Status
Malfunction detected in cylinder #8 ionization (ION) sensor/circuit. ECM cannot read expected ionization signal for cylinder #8; MIL illuminated.
Repair difficulty: Medium
Diagnostic time: 1.0 - 3.0 hours
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