P1315 - FAULT CODE - OBD2

P1315 GM: IGNITION COIL 4 PRIMARY FEEDBACK CIRCUIT.

P1315 TOYOTA, LEXUS, PONTIAC: IGNITION CONTROL - CYLINDER NO. 4 - MALFUNCTIONING CIRCUIT. 4 - CIRCUIT MALFUNCTION.

P1315 BUICK, CADILLAC: IGNITION COIL 4 PRIMARY FEEDBACK CIRCUIT.

P1315 CHEVROLET: IGNITION COIL 4 CONTROL - FEEDBACK CIRCUIT MALFUNCTION.

The Direct Ignition System (DIS) avoids the use of distributors to deliver the ignition spark to the cylinders, using instead the signals produced by the CMP Sensor (Camshaft Position Sensor) or the CKP Sensor (Crankshaft Position Sensor). With this data, the Powertrain Control Module (PCM) determines the most appropriate ignition timing, taking into account the vehicle’s engine speed and load. To achieve the most accurate ignition timing possible, the igniter is used. This also prevents high voltage levels from being lost, thus allowing the service life of these components to be increased.

The cylinders that are connected to the coil receive an ignition signal from the igniter. The PCM determines when it is the most appropriate time to send the ignition signal. After the ignition signal is received by the igniter, it is transmitted to the primary winding so that the coil passes it to the corresponding cylinder.

Although the voltage produced by the spark ignites the fuel mixture, the PCM needs to know the voltage that assists cylinder ignition. For this reason, an IGF (Ignition Feedback) signal is provided to the PCM after the primary signal has been interrupted. If this feedback signal is deficient or its strength is not adequate, the P1315 OBDII diagnostic code will be set

• Check Engine light ON.
• Higher fuel consumption.
• Loss of engine power.
• Unexpected engine stoppage.
• Instabilities during idling.
• There are misfires.

Reasons for setting the  DTC P1315 OBD2 code:

• The igniter circuit may have bad wires or connectors.
• An ignition coil may be faulty.
• The cigarette lighter may be damaged.

To troubleshoot the P1315 OBDII fault code, follow these steps:

• To start diagnosing this code, consult the TSBs as a first step. It will be very useful the information you find there.
• Place the engine at idle speed and verify that the coils and spark plugs are not malfunctioning. Make any necessary repairs or replacements.
• Check that the ignition coil voltages are right for the proper ignition system performance. If you detect inconsistencies in these voltages or determine that one of these is in bad condition, make the appropriate adjustments.
• Referring to the vehicle's data source, locate the IGF and IGT circuits that correspond to the problem cylinder. Then, verify that the circuit is not shorted and that the resistance and continuity of the circuit are right. Fix if necessary.
• With the igniter active, make some voltage tests on the wiring that provides ground as well as on the PCM Compare the actual values with those specified. If you find some differences, repairs or replacement of the igniter should be made as necessary.