GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Chevy C Cab/Chassis HD (GMT 400) 🢒 Engine 🢒 Engine Controls - 6.5L (L65) 🢒 DTC P1218

Circuit Description

The powertrain control module (PCM) uses a calibrated resistor mounted internally in the fuel 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 ignition is ON.

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 control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC
    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with 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 is 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.

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

Test Description

The number below refers to the step number 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. This DTC will only clear DTC Status when a Time Set procedure has been activated (injection timing does not have to be adjusted).

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Are than any other DTCs set?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

  1. Check the connection at the fuel solenoid driver.
  2. Clear the DTC and cycle the ignition.
  3. Start and idle the engine.
  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 and Select DTC, Specific, then enter the DTC number.

Does the scan tool indicate that the diagnostic passed?

Go to Intermittent Conditions

Go to Step 4

4

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

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

Did you complete the replacement?

Go to Step 5

--

5
  1. Use the scan tool in order to clear the DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

Go to Step 6

Go to Step 1

6

With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK