P2306 — Ignition Coil "C" Primary Control Circuit Low
P2306 — Ignition Coil "C" Primary Control Circuit Low. A fault in the ignition system. Short, gentle driving to a shop is usually possible. Typical causes: faulty ignition control circuit in the ECM, failed ignition coil or coil pack, moisture or oil in the spark plug wells.
powertrain (engine/transmission)
Is it safe to drive?
Drive with caution Drive with caution and avoid load. Ignition faults cause misfires that quickly overheat and destroy the catalytic converter; if the Check Engine Light flashes, stop and fix it first.
How to diagnose with an OBD scanner
- Read the code and freeze frame Connect an OBD2 scanner, confirm P2306 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
- Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
- Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the ignition system for damage, corrosion, chafing or poor contact.
- Subsystem check Check for supply voltage at the ignition coil "C" primary control connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
- Subsystem check Swap the coil to another cylinder and see if the fault code follows it.
- Subsystem check Inspect spark plugs for wear, oil or carbon tracks and check plug gaps.
- Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2306 does not return.
Approximate repair cost
Repair cost depends on which component actually failed. Typical scenarios for P2306 (parts and labor, USD, independent shop rates): Replace an ignition coil: $150–$380; Repair coil wiring or connector: $80–$250; Replace spark plugs: $90–$250. Overall, fixing P2306 usually costs between $80 and $380. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.
Common questions
How do I diagnose P2306 myself?
Start with a scan: confirm P2306, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the ignition coil "C" primary control, and verify the suspect component against live data before buying parts.
What does OBD2 code P2306 mean?
P2306 — Ignition Coil "C" Primary Control Circuit Low. A fault in the ignition system. Short, gentle driving to a shop is usually possible. Typical causes: faulty ignition control circuit in the ECM, failed ignition coil or coil pack, moisture or oil in the spark plug wells.
Is it safe to drive with P2306?
Drive with caution and avoid load. Ignition faults cause misfires that quickly overheat and destroy the catalytic converter; if the Check Engine Light flashes, stop and fix it first.
How much does it cost to fix P2306?
Replace an ignition coil — $150–$380; Repair coil wiring or connector — $80–$250; Replace spark plugs — $90–$250. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.
Will P2306 clear itself?
Sometimes P2306 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.
What does P2306 mean?
When P2306 appears on a scan, it means the control module has flagged a problem in the ignition system: ignition coil "C" primary control circuit low. The fault sits in the powertrain (engine/transmission) group of the OBD2 standard.
“Circuit low” means the voltage on the ignition coil "C" primary control circuit stays below the expected minimum — close to ground. The usual physical reasons are a short to ground, a chafed wire touching metal, a missing supply voltage, or a failed component dragging the signal down.
The module monitors this system continuously while driving. When readings fall outside the expected range for a defined number of drive cycles, it stores P2306 and switches on the warning light. Freeze frame data saved with the code shows the exact conditions — rpm, load, temperature, speed — at the moment the fault was detected, which is the best starting point for diagnosis.
What causes P2306?
- signal wire shorted to ground (chafed insulation)
- failed ignition coil "C" primary control pulling the signal low
- missing supply voltage to the ignition coil "C" primary control
- damaged coil wiring or connector
- moisture or oil in the spark plug wells
- failed ignition coil or coil pack
- worn spark plugs or wrong plug gap
Common symptoms of P2306
- misfires under load or at idle
- Check Engine Light on
- loss of power and jerking
- increased fuel consumption
- hard starting, especially in damp weather
How to diagnose P2306
- Connect an OBD2 scanner, confirm P2306 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
- Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
- Visually inspect the wiring harness and connectors related to the ignition system for damage, corrosion, chafing or poor contact.
- Check for supply voltage at the ignition coil "C" primary control connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
- Swap the coil to another cylinder and see if the fault code follows it.
- Inspect spark plugs for wear, oil or carbon tracks and check plug gaps.
- Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2306 does not return.
How to fix P2306
Start with the cheapest and most common causes before replacing expensive parts:
- Replace an ignition coil — $150–$380
- Repair coil wiring or connector — $80–$250
- Replace spark plugs — $90–$250
How much does it cost to fix P2306?
Repair cost depends on which component actually failed. Typical scenarios for P2306 (parts and labor, USD, independent shop rates):
- Replace an ignition coil: $150–$380
- Repair coil wiring or connector: $80–$250
- Replace spark plugs: $90–$250
Overall, fixing P2306 usually costs between $80 and $380. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.
Can you drive with P2306?
Drive with caution and avoid load. Ignition faults cause misfires that quickly overheat and destroy the catalytic converter; if the Check Engine Light flashes, stop and fix it first.