Code Definition

P1315 — Igniter circuit malfunction - No. 4

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Lexus

About P1315

P1315 is a manufacturer-specific powertrain diagnostic trouble code recorded for Lexus vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1315 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1315 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

This Lexus ECM fires each ignition coil through an igniter using an IGT timing command and confirms successful firing through an IGF feedback signal returned to the ECM. DTC P1315 sets when the ECM commands the number 4 igniter circuit but does not see a correct IGF confirmation, or it detects an electrical fault in that circuit. The usual cause is a number 4 coil or igniter that is not firing properly, or an IGT or IGF wiring fault on that circuit. With this code stored the engine may misfire, idle roughly, lose power, or be difficult to start.

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