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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 S10 Pickup - 2WD 🢒 Engine 🢒 Engine Controls - 2.2L (L43) 🢒 DTC P0301-P0304

System Description

The powertrain control module (PCM) uses information from the ignition control (IC) module and the camshaft position (CMP) sensor in order to determine when an engine misfire is occurring. By monitoring the variations in the crankshaft rotation speed for each cylinder the PCM is able to detect individual misfire events. A misfire rate that is high enough can cause the three-way catalytic converter to overheat under certain conditions. The malfunction indicator lamp (MIL) will flash ON and OFF when the conditions for three-way catalytic converter overheating are present.

Conditions for Running the DTC
    • The engine speed is between 469-5,906 RPM
    • The battery voltage is between 9-17 volts
    • The engine coolant temperature (ECT) is between -7 to 123°C (20-254°F).
    • The engine has been running more than 5 seconds
    • The fuel level is above 10 percent

Conditions for Setting the DTC

The PCM is detecting a crankshaft rotation speed variation indicating a misfire rate sufficient to cause emissions levels to exceed mandated standard.

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

An intermittent diagnostic trouble code (DTC) can also be the result of a defective reluctor wheel. Remove the crankshaft position (CKP) sensor and inspect the reluctor wheel through the crankshaft sensor mount hole. Check the porosity and the condition of the reluctor wheel.

Test Description

The numbers below refer to the step numbers on the diagnostic table:

  1. Whenever a DTC P0108 is present, verify that no misfire is present by viewing the misfire counters. DTC P0108 may set as a result of a misfire.

    2.

  2. A visual and physical inspection should include checking the following conditions:

    3. • The wiring for proper connections, pinches and cuts.
    • Clean and tight PCM grounds.
    • The vacuum hoses for splits, kinks and proper connections as shown on the vehicle emission information label. Check thoroughly for any type of leak or restriction.

  1. This step determines if the Misfire DTC is the result of a hard malfunction or an intermittent condition.

    2.

  2. If the misfire is not present, operate the vehicle under the conditions found in the Freeze Frame Data in order to detect the misfire. Depending on the engine load, the conditions may have to be maintained for up to 20 seconds. If the misfire accumulators start to increment, the misfire is present. A history misfire counter will record the number of misfires that occur until the DTC is cleared. The current counter must count a total of at least 195 misfires before the history counter begins storing the misfire information.

    3.

  3. No spark on one coil may be caused by an open secondary circuit. Therefore, the coils secondary resistance should be checked.

    4.

  4. Use the injector test lamp to test the harness wiring and for PCM control of the injectors.

    5.

  5. Perform the Fuel Inj Coil Test on the misfiring cylinder only.

    6.

  6. Determines if the injector driver circuit is shorted to ground, voltage or if the PCM is malfunctioning.

    7.

  7. Replace any spark plugs that are worn, cracked, or fouled.

    8.

  8. Since the voltage is supplied to the injector on a single circuit before the injector harness, the malfunction may only be a poor connection or an open in the injector harness. An open before the harness may result in a Cranks But Does Not Run complaint.

    9.

  9. A basic engine problem that affects only a single cylinder is possible at this point (i.e. valve train, compression, etc.).

Step

Action

Values

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 any component DTCs set?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

  1. Perform a visual and physical inspection. Refer to Symptoms - Engine Controls .
  2. Make any necessary repairs.

Were any repairs necessary?

--

Go to Step 6

Go to Step 4

4

With the engine idling, install a scan tool.

Is the misfire current counter incrementing on the cylinder that had a misfire DTC?

--

Go to Step 5

Go to Step 6

5
  1. Turn OFF the engine.
  2. Disconnect the fuel injector harness connectors.
  3. Install the J 26792 Spark Tester on the spark plug cable for the cylinder that indicated a misfire.
  4. Remove the spark plug cable from the cylinder on the same ignition coil housing and install a jumper wire from the spark plug connector of the ignition coil housing to ground.
  5. Crank the engine with the remaining spark plugs cables still connected.

Does the spark tester spark?

--

Go to Step 8

Go to Step 9

6

  1. Turn ON the ignition, with the engine OFF.
  2. Review the Freeze Frame data and note parameters.
  3. Operate vehicle within the Freeze Frame conditions and Conditions for Running the DTC as specified in the supporting text.

Is the misfire current counter incrementing on the cylinder that indicated a misfire?

--

Go to Step 5

Go to Step 7

7

Was a repair made from the visual and physical inspection?

--

Go to Step 30

Go to Diagnostic Aids

8
  1. Remove the spark plug from the misfiring cylinder.
  2. Change the spark plug with a spark plug from a known good cylinder.
  3. Reconnect the fuel injector harness connector.
  4. Run the vehicle within the misfire conditions as noted from the Freeze Frame data.

Is the misfire current counter incrementing on the cylinder that indicated a misfire?

--

Go to Step 13

Go to Step 22

9
  1. Remove the spark plug cable from the misfiring cylinder.
  2. Use a DMM in order to measure the resistance of the spark plug cable.

Is the spark plug cable resistance less than the specified value?

1,000 ohms/in

Go to Step 10

Go to Step 23

10

  1. Remove the ignition coil from the cylinder that did not fire.
  2. Use a DMM in order to measure the ignition coils secondary resistance.

Is the resistance within the specified range?

5-8 K ohms

Go to Step 11

Go to Step 24

11
  1. Replace the ignition coil with a known good one.
  2. Crank the engine and check for spark.

Did spark occur on the spark tester?

--

Go to Step 24

Go to Step 12

12
  1. Visually inspect the ICM 6 pin harness connector to see if the connections are clean and tight.
  2. Repair the connection as necessary. Refer to Connector Repairs in Wiring Systems.

Were any repairs necessary?

--

Go to Step 30

Go to Step 25

13

  1. Turn OFF the engine.
  2. Disconnect the 4 fuel injector harness connectors from the injectors.
  3. Install anJ 34730-405 Injector Test Lamp on the injector harness connector for the misfiring cylinder.
  4. Crank the engine and note the lamp.

Does the fuel injector test lamp blink?

--

Go to Step 14

Go to Step 15

14

Perform the Injector Coil/Balance Test Procedure . Refer to Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Between 10-35 Degrees C (50-95 Degrees F) .

Is the fuel injector OK for the cylinder that had indicated a misfire?

--

Go to Step 28

Go to Step 29

15
  1. Disconnect the fuel injector test lamp.
  2. Connect a test lamp to ground, probe the misfiring cylinder fuel injector harness connector ignition positive voltage terminal.
  3. Turn ON the ignition, with the engine OFF.

Did the test lamp illuminate?

--

Go to Step 16

Go to Step 27

16

  1. Connect a test lamp to ground.
  2. Disconnect the fuel injector harness connectors.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the fuel injector harness connector control circuit terminal for the cylinder that indicated a misfire.

Did the test lamp remain OFF?

--

Go to Step 17

Go to Step 26

17
  1. Connect the test lamp to B+.
  2. Probe the fuel injector control circuit terminal.

Did the test lamp remain OFF?

--

Go to Step 18

Go to Step 19

18

Inspect the fuel injector harness connector and the PCM harness connectors and connections for an open circuit. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Are the connections OK?

--

Go to Step 20

Go to Step 21

19
  1. Check for a short to ground in the fuel injector control circuit for the cylinder that indicated a misfire.
  2. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 30

Go to Step 20

20

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 30

--

21

Repair the connector or connections. Refer to Connector Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 30

--

22

Replace the malfunctioning spark plug. Refer to Spark Plug Replacement .

Did you complete the replacement?

--

Go to Step 30

--

23

Replace the spark plug cable. Refer to Spark Plug Wire Replacement .

Did you complete the replacement?

--

Go to Step 30

--

24

Replace the defective ignition coil. Refer to Ignition Coil Replacement and Ignition Control Module Replacement .

Did you complete the replacement?

--

Go to Step 30

--

25

Replace the ICM. Refer to Ignition Coil Replacement and Ignition Control Module Replacement .

Did you complete the repair?

--

Go to Step 30

--

26
  1. Check for a short to voltage in the misfiring cylinder fuel injector control circuit.
  2. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 30

Go to Step 20

27

Repair the open ignition positive voltage circuit for the fuel injector. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 30

--

28

Check for a basic engine problem, refer to Symptoms - Engine Mechanical in Engine Mechanical 2.2L (L43).

Did you complete the repair?

--

Go to Step 30

--

29

Replace the malfunctioning fuel injector. Refer to Fuel Injector Replacement .

Did you complete the repair?

--

Go to Step 30

--

30
  1. Use the scan tool in order to clear the DTCs.
  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 31

Go to Step 2

31

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