Circuit Description
The injection pump delivers fuel to individual cylinders by opening and closing a solenoid control fuel valve. The PCM monitors the amount of time it takes for the fuel solenoid valve to physically close after commanded to close. Closure time out of range is seen as a fault. This response time is measured in milliseconds.
Conditions for Running the DTC
• The battery voltage is greater than 12 volts and less than 15 volts.
• The engine coolant temperature is greater than 50°C (122°F).
• The engine speed is greater than 1350 RPM.
• The requested fuel rate is greater than 0.0 mm
Conditions for Setting the DTC
• The inj. pump closure time less than.75 ms.
• All diagnostic set conditions met for 2 seconds.
Action Taken When the DTC Sets
• The malfunction indicator lamp (MIL) will not illuminate.
• The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Failure Records.
Conditions for Clearing the MIL/DTC
• 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 also possible that a P0251, P0370 and P1216 will set if the vehicle has run out of fuel. Customer driving habits should be checked to determine if the 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. When the PCM is in backup fuel, fast idle and poor performance problems will exist. If P0251 is also stored, the snap shot mode on the scan tool should be used to properly identify the fault. DTCs P0335, P1216, and P1217 may set along with this DTC. If DTC P1216 is set with any other DTCs, diagnose them first. If the vehicle is running close to the DTC setting closure time, the vehicle should be checked during cold start ups and during hot conditions.
An intermittent can be caused by the following:
• Poor connections
• Rubbed through wire insulation
• Broken wire inside the insulation
Test Description
Numbers) below refer to the step number(s) on the Diagnostic Table.
2. This step will determine if the ground circuit is open which causes the vehicle not to start.
3. This step will determine if the signal circuit is open or an injection pump (fuel solenoid) is at fault.
