P1300 GMC Code - Ignition Coil 1 Primary Feedback Circuit

The Diagnostic Trouble Code (DTC) Ignition Coil Primary Feedback Circuit monitors the primary circuitry of individual ignition coils for successful completion of an ignition event. The ignition trigger signal and ignition fail-safe input signal provide crucial information in the control of ignition system timing and activation of the fail-safe function. Based on the initial timing angle, calculated from the crankshaft and the camshaft position signals, Powertrain Control Module (PCM) calculates the ignition trigger signal. The ignition trigger signal is then sent to the ignition control circuitry located in each ignition coil. Ignition control circuitry initiates the ignition dwell period by commanding the power transistor ON. When PCM determines the proper time to provide a spark, the PCM turns OFF the ignition trigger signal. In response to the PCM signal, the ignition coil control circuitry turns OFF the power transistor, producing a high voltage discharge from secondary coil windings. After a spark has occurred, the control circuitry sends an ignition fail-safe input signal back to the PCM, confirming that an ignition event has taken place. If the ignition fail-safe input signal is not received by the PCM, a cylinder-specific DTC will be set.
Anytime the fail-safe input signal is lost, engine operation will enter the fail-safe function. If engine load exceeds certain parameters during fail-safe function, FUEL CUT-OFF mode is activated, and fuel injector operation is ceased. The suspension of fuel injection in FUEL CUT-OFF mode protects the catalytic converter from damage. Damage can occur when excess unburned fuel reaches the converter and causes the catalyst to overheat.

• Faulty Ignition Coil 1
• Ignition Coil 1 harness is open or shorted
• Ignition Coil 1 circuit poor electrical connection
• Faulty Powertrain Control Module (PCM)