Circuit Description
WARNING: This page is about a different car, the 2003 GMC Sierra and 2003 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The Fuel Injector Control Module (FICM) monitors the CNG Fuel Tank Pressure (FTP) sensor voltage, the Fuel Tank Temperature (FTT) sensor voltage, and the Fuel Rail Temperature (FRT) sensor voltage. The FTP, FTT, and FRT sensor values, and diagnostic data, is communicated to the Powertrain Control Module (PCM) by 2 Pulse Width Modulated (PWM) circuits. This DTC sets when the PCM does not receive any PWM signals from the FICM.