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 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.
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 stores 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. |
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. Its also possible that a P0251,
P0370 and P1216 will set if vehicle has run out of fuel. Customer driving
habits should be checked to determine if vehicle has been performing
in these manners. If it has been determine that the vehicle has been
performing in these conditions, bleed fuel system of all air and test
drive vehicle.
When 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 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, vehicle should
be checked during cold start ups and during hot conditions.
An intermittent can be caused by the following:
| • | Rubbed through wire insulation |
| • | Broken wire inside the insulation |
