GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 Savana 🢒 DTC 🢒 DTC P1218 Injection Pump Calibration Circuit

Object Number: 426020 Size: LF
Engine Controls Components
Cell 22: Fuel Controls
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The powertrain control module (PCM) uses a calibrated resistor which is mounted internally in the injection pump in order to determine the 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 ignition switch is in the ON position.

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 illuminates the malfunction indicator lamp (MIL) on the second consecutive drive trip 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 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 MIL/DTC
    • The PCM will turn the MIL off after 3 consecutive trips without a fault condition.
    • A history DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
    • The scan tool Clear Info function was used.

Diagnostic Aids

Check the connection at fuel injector driver. Clear the DTC, and the cycle ignition. If the DTC clears, treat the condition as an intermittent.

Test Description

The number(s) below refer to the step number(s) on the Diagnostic Table.

  1. This step will determine if there is a problem with the connection at the fuel solenoid driver or a malfunctioning injection pump.

Step

Action

Value(s)

Yes

No

1

Important: Before clearing the DTCs, use the scan tool Capture Info function to save the Freeze Frame and the Failure records for reference. The control module's data is deleted once the Clear Info function is used.

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Are than any other DTCs set?

--

Go to applicable DTC Table

Go to Step 3

3

  1. Check the connection at the fuel solenoid driver.
  2. Clear the DTC and the cycle ignition.
  3. Start the engine and allow the engine to idle.
  4. Activate the Time Set procedure (the diagnostic will only run when a Time Set procedure is performed).
  5. Exit out of the Time Set procedure.
  6. Select DTC and the Specific DTC function.
  7. Enter the DTC number that was set.

Does the scan tool indicate that this diagnostic Ran and Passed?

--

Go to Step 5

Go to Step 4

4

Important: The new injection pump must be timed. Refer to Fuel Injection Pump Timing Adjustment .

Replace the fuel injection pump. Refer to Fuel Injection Pump Replacement .

Is the action complete?

--

Go to Step 6

--

5

The DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If additional DTCs were stored, refer to those table(s).

Are any additional DTCs stored?

--

Go to the applicable DTC Table

Go to Diagnostic Aids

6

Does the scan tool display any additional undiagnosed DTCs?

--

Go to the applicable DTC Table

System OK