Generic
Type:
    Powertrain - Ignition System or Misfire - ISO/SAE Controlled
Description:
    Ignition/Distributor Engine Speed Input Circuit No Signal

GM
Type:
    Powertrain - Ignition System or Misfire - ISO/SAE Controlled
Description:
    ICM 4X Reference Circuit No Frequency Conditions
Cause:
    DTC P0340 and P1376 not set, CMP sensor signals received, and the PCM did not detect any 4X fuel control pulses for 4 seconds