GM/Detroit 6.5L ENGINE CONTROLS – DTC P1218 Injection Pump Calibration Circuit

Circuit Description
The PCM uses a calibrated resistor mounted internally in the injection pump to determine fuel rates. The resistor value is stored in the PCM memory. If the PCM memory has been disturbed or the PCM has been replaced, the PCM will relearn the resistor value on the next ignition cycle.

Conditions for Running the DTC
• The PCM currently does not have a valid resistor valve.
• The PCM is unable to read a resistor value.

Conditions for Setting the DTC
• The PCM currently does not have a valid resistor valve.
• The PCM is unable to read a resistor value.

Action Taken When the DTC Sets
• The PCM will default to the lowest fuel table.
• The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive drive trip that the diagnostic runs and fails.
• The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the Failure Records will store this information. If the diagnostic reports a failure on the second consecutive drive,.trip, the Freeze Frame records the operating conditions at the time of failure and updates the Failure Records.

Conditions for Clearing the MIUDTC
• The PCM will turn the MIL off after three consecutive trips without a fault condition.
• A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures
• The use of a scan tool .

Diagnostic Aids
Intermittent DTCs (P0251, P0370 and P1216) may be caused by air entering the fuel system when fuel levels get below 1 /8 of a tank while performing hard acceleration or turning maneuvers. It’s a l so possible that a P0251, P0370 and P1216 will set if vehicl e has run out of fuel. Customer driving habits should be checked to determine if vehicle has been performing in these manners. If the vehicle has been performing in these conditions, bleed the fuel system of all air and test drive the vehicle.
Check the connection at the fuel injector driver. Clear DTC, and cycle ignition. If DTC clears, treat condition as an intermittent.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
3. This step will determine if there is a problem with the connection at the fuel solenoid driver or malfunctioning injection pump. This DTC will only clear DTC Status when a Time Set procedure has been activated (injection timing does not have to be adjusted).

 

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