Engine Backfires: Sensor/System

Check the following:

• Monitor the 24X sensor and the Camshaft Position (CMP) sensor signal present parameters on the scan tool. If both are not responding, test the sensor feed circuit. Both sensors use a separate feed circuit but are internally connected to power. Check all CKP sensor "A" and CMP sensor circuits for intermittents. See INTERMITTENTS  .
• Monitor the 3X parameter on the scan tool. If the 3X is not responding, check the CKP sensor "B" and circuits for intermittents. Check the Ignition Control (IC) circuit, IC timing control circuit, low resolution engine speed signal circuit and the low reference circuit for intermittents. If these circuits become open, or shorted may not set a DTC immediately, but are capable of causing driveability complaints.
• Check the Mass Airflow (MAF) sensor conditions. Ensure that the MAF sensor honeycomb is not damaged.