P1215

DTC P1215

Circuit Description

The Alternative Fuels ECM contains electronic devices called output driver modules. The output driver modules provide switchable outputs for operating solenoids, relays, telltales, and other devices. Each of the outputs has a status line that the Alternative Fuels ECM monitors.


In order for the status line to detect a failure, the state of the control circuit must be opposite of the commanded state. If the Alternative Fuels ECM is commanding an output ON, then 0 volts should be monitored by the status line. If the Alternative Fuels ECM is commanding an output OFF then the voltage supplied to the controlled device should be monitored by the status line.


This DTC sets when the Alternative Fuels ECM has detected a control circuit fault.


Monitored control circuits include the following components:

* The Alternative Fuels Operation (AFO) Signal control circuit
* The Low Pressure Lock-Off (LPL) solenoid control circuit
* The High Pressure Lock-Off (HPL) solenoid control circuit



Conditions for Running the DTC

The engine is cranking or running.


Conditions for Setting the DTC

The Alternative Fuels ECM monitors a control circuit fault for at least 2 second continuously.


Action Taken When the DTC Sets

* The Alternative Fuels ECM will switch over to gasoline operation on KL6 equipped vehicles.
* The Alternative Fuels ECM will illuminate the MIL and store the DTC as History during 1 drive trip in which the diagnostic runs and fails.
* The Alternative Fuels ECM will record operating conditions at the time the DTC sets. This information will be stored as Freeze Frame data.



Conditions for Clearing the MIL/DTC




* The Last Test Failed status will clear when the DTC runs and passes.
* The Alternative Fuels ECM will turn OFF the MIL after 3 consecutive drive trips that the DTC runs and passes.
* The History status will clear after 40 consecutive WARM-UP cycles with NO failures of ANY DTC.
* All DTC Information can be cleared with a scan tool.



Diagnostic Aids

This DTC may also set after service programming of the powertrain control module (PCM). Clear DTC Information after PCM programming is complete.


The scan tool Output Driver data displays are only functional when the vehicle is operating on CNG.


Test Description

The number below refers to the step number on the diagnostic table.
2. The AFO Signal data parameter is from the PCM and displays the observed state of the alternative fuels operation command circuit. The AFO Signal Command data parameter is from the alternative fuels ECM and displays the commanded state of the alternative fuels operation command circuit.
11. The alternative fuels ECM should only command the HPL solenoid ON for about 2 seconds. If the test lamp is always OFF test for control circuit continuity. If the test lamp is always ON test for a control circuit shorted to ground.