Code
P1300
GMC
P — Powertrain
Ignitor Circuit
Views:
UK: 33
EN: 69
RU: 42
AI status
Completed
Completed
100%
Causes
- Open or shorted wiring in ignitor/ignition module primary circuit
- Loose, corroded, or damaged connector at ignitor or coil
- Failed ignitor (ignition module) or ignition coil
- Poor power (battery/ignition feed) or ground to ignitor
- Faulty crankshaft or camshaft position sensor (missing trigger)
- PCM/ECM driver circuit failure or internal fault
Symptoms
- Check Engine light (MIL) on
- Engine misfire, rough idle, or hesitation
- Hard start or no-start condition
- Intermittent loss of spark on one or more cylinders
- Possible reduced power or stalling
What to check
- Read freeze frame and live data with a scan tool; note related codes (misfire, coil codes, cam/crank sensor codes)
- Visually inspect ignitor, coils, connectors, wiring harness for damage or corrosion
- Verify battery voltage at ignition feed circuit with key on/crank
- Check ground continuity to ignitor mounting/connector
- Backprobe ignitor primary trigger and power leads while cranking; measure presence of trigger pulses
- Inspect crankshaft/camshaft position sensor signals if triggers are missing
Signal parameters
- Ignitor primary feed: battery voltage (approx. B+ with key ON/CRANK)
- Ignitor ground/driver: pulsed switching to ground from PCM/ignitor when cranking (frequency proportional to engine speed)
- Trigger input: cam/crank position sensor pulse present at ignitor/PCM when cranking
- Typical fault condition: no trigger pulses, intermittent pulses, or shorted/low voltage on feed/ground
Diagnostic algorithm
- Retrieve codes and freeze frame data. Note other stored codes (P03xx, P035x, P06xx, cam/crank sensor codes). Clear codes and attempt to reproduce.
- Perform a visual inspection of the ignitor, ignition coils, connectors, and wiring for heat damage, corrosion, or broken wires. Repair any obvious damage.
- Check battery voltage at the ignitor power terminal with key ON and while cranking. Voltage should be near battery voltage. Repair supply if low or intermittent.
- Check ground continuity from ignitor ground terminal to chassis negative. Clean and tighten ground connections as needed.
- Backprobe the ignitor trigger/driver circuit with a lab scope or DVOM (frequency/voltage) while cranking. Confirm trigger pulses are present and within expected characteristics. If pulses are absent, trace back to crank/cam sensors and PCM.
- Measure primary coil/ignitor input and output per service manual (resistance where applicable). Replace coil/ignitor if out of specification or intermittent.
- If wiring, supply, and ground are good but the ignitor does not respond, substitute a known-good ignitor or ignition coil assembly (if available) to verify operation before replacing PCM.
- If ECM/PCM driver suspected after verifying wiring and components, consult vehicle-specific procedures for PCM diagnosis/repair. Avoid replacing the PCM without full verification.
- Safety note: ignition circuits can produce high voltage. Take appropriate precautions and follow manufacturer service manual procedures.
Likely causes
- Damaged wiring or poor connector at the ignitor
- Failed ignitor/ignition module
- Loss of battery feed or ground to ignitor
- Ignition coil failure affecting ignitor operation
- Faulty PCM driver (less common)
Fault status
Status
Ignitor circuit malfunction detected — possible ignition module, wiring, power/ground, or PCM driver issue.
Repair difficulty: Medium
Diagnostic time: 1.0 - 3.0 hours
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