P2315 — Ignition Coil "F" Primary Control Circuit Low
OBD2 code P2315 flags a problem with the ignition system (ignition coil "F" primary control circuit low). Short, gentle driving to a shop is usually possible. Common culprits: failed ignition coil or coil pack, damaged coil wiring or connector, worn spark plugs or wrong plug gap.
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 P2315 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 "F" 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 P2315 does not return.
Approximate repair cost
Repair cost depends on which component actually failed. Typical scenarios for P2315 (parts and labor, USD, independent shop rates): Repair coil wiring or connector: $80–$250; Replace an ignition coil: $150–$380; Replace spark plugs: $90–$250. Overall, fixing P2315 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
What is the most common cause of P2315?
The most common causes are: failed ignition coil or coil pack, damaged coil wiring or connector, worn spark plugs or wrong plug gap.
What does OBD2 code P2315 mean?
OBD2 code P2315 flags a problem with the ignition system (ignition coil "F" primary control circuit low). Short, gentle driving to a shop is usually possible. Common culprits: failed ignition coil or coil pack, damaged coil wiring or connector, worn spark plugs or wrong plug gap.
How much does it cost to fix P2315?
Repair coil wiring or connector — $80–$250; Replace an ignition coil — $150–$380; 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.
What are the symptoms of P2315?
Drivers most often notice: misfires under load or at idle, hard starting, especially in damp weather, increased fuel consumption, Check Engine Light on.
How do I diagnose P2315 myself?
Start with a scan: confirm P2315, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the ignition coil "F" primary control, and verify the suspect component against live data before buying parts.
What does P2315 mean?
Seeing P2315 on your scanner? The control unit has caught the ignition system operating outside its calibrated window. The formal description is “Ignition Coil "F" Primary Control Circuit Low”, and the code is grouped under powertrain (engine/transmission) faults.
“Circuit low” means the voltage on the ignition coil "F" 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.
This code does not appear from a single bad reading: the module must see the fault condition repeat under defined operating conditions before it turns on the warning light. The freeze frame captured with P2315 — engine load, rpm, temperature, speed — tells you exactly when the problem occurs, so reproduce those conditions when testing.
Common symptoms of P2315
- misfires under load or at idle
- hard starting, especially in damp weather
- increased fuel consumption
- Check Engine Light on
- loss of power and jerking
What causes P2315?
- signal wire shorted to ground (chafed insulation)
- missing supply voltage to the ignition coil "F" primary control
- failed ignition coil "F" primary control pulling the signal low
- worn spark plugs or wrong plug gap
- faulty ignition control circuit in the ECM
- damaged coil wiring or connector
- moisture or oil in the spark plug wells
- failed ignition coil or coil pack
How to diagnose P2315
- Connect an OBD2 scanner, confirm P2315 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 "F" 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 P2315 does not return.
How to fix P2315
Start with the cheapest and most common causes before replacing expensive parts:
- Repair coil wiring or connector — $80–$250
- Replace an ignition coil — $150–$380
- Replace spark plugs — $90–$250
How much does it cost to fix P2315?
Repair cost depends on which component actually failed. Typical scenarios for P2315 (parts and labor, USD, independent shop rates):
- Repair coil wiring or connector: $80–$250
- Replace an ignition coil: $150–$380
- Replace spark plugs: $90–$250
Overall, fixing P2315 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 P2315?
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.