DTC P1310 Toyota: Ignition Circuit Malfunction (Cylinder 3)
Code Meaning
The P1310 code indicates a problem in the ignition circuit for cylinder 3. The Direct Ignition System (DIS) uses a dedicated coil per cylinder. The ECM sends an IGT signal to the coil to trigger the spark. After ignition, the coil sends a confirmation IGF signal back to the ECM. P1310 is triggered when the ECM does not receive the IGF signal from cylinder 3 during engine operation.
Common Symptoms
- 🔶 Check Engine light on (or “Service Engine Soon”)
- ⚠️ Engine in limp mode (loss of power)
- 🚗 Rough idling
- ⛽ Increased fuel consumption
- 💥 Cylinder 3 misfires
Possible Causes
- Ignition Coil Failure
- Coil #3 damaged or inoperative.
- Wiring Problems
- Short circuit or open circuit in the #3 coil harness.
- Damaged, melted, or exposed wires.
- Faulty Electrical Connections
- Loose, corroded, or oxidized coil connector.
- Bent, broken, or pushed-back pins in the connector.
- Engine Control Module (ECM) Failure
- Internal ECM problem (less common, check last).
Diagnostic and Repair Procedure
- Visual Inspection
- Inspect the #3 coil connector and harness: look for damage, corrosion, or burn marks.
- Check the condition of the pins (no bending, breakage, or dislodgement).
- Electrical Tests
- Check the coil resistance (according to manufacturer specifications).
- Test for continuity and absence of short circuits in the wiring using a multimeter.
- Check the circuit’s power supply voltage and ground.
- Advanced Diagnostics
- Swap coil #3 with another cylinder: if the code follows the coil, replace it.
- Use an oscilloscope to analyze the IGT/IGF signals.
- Check the ECM live data with a diagnostic tool.
- Repairs
- Replace the faulty coil.
- Repair or replace the damaged harness.
- Clean the connectors or replace the faulty connector.
- As a last resort, update or replace the ECM.
⚠️ Precautions: Always disconnect the battery before any work on the ignition circuit.
Key DIS System Operation
| Signal | Role | Fault |
|---|---|---|
| IGT | Ignition command sent by the ECM to the coil | No spark |
| IGF | Ignition confirmation signal returned by the coil to the ECM | Triggers P1310 |
Recommended Additional Sources
- Toyota repair manual specific to the model
- ETM (Electrical Troubleshooting Manual) wiring diagrams
- TSB (Technical Service Bulletin) related to P1310