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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 1995 🢒 Sunfire 🢒 DTC 🢒 DTC P0200 Injector Control Circuit

Circuit Description

The powertrain control module (PCM) has four injector driver circuits, each of which controls an injector. The PCM monitors the current in each driver circuit by measuring a voltage drop through a fixed resistor and is able to control it. The current through each driver is allowed to rise to a PEAK of 4 amps to quickly open the injectors and is reduced to 1 amp to HOLD them open. This is call PEAK and HOLD. If the current can't reach a 4 amp peak, a DTC is set. This DTC is also set if an injector driver is shorted to voltage.

Conditions for Setting the DTC
    • Injector current is less than 4 amps.
    • Battery voltage is more than 9 volts.
    • Above conditions met for 10 seconds.

Action Taken when the DTC Sets

Malfunction indicator lamp (MIL) illuminates.

Conditions for Clearing the DTC
    • The MIL will turn OFF after passing three consecutive diagnostic tests.
    • A history DTC will clear after 40 consecutive ignition cycles have occurred without a fault.
    • History and current DTCs can be cleared by using a scan tool.

Diagnostic Aids
    • An injector driver circuit that is open or shorted to voltage will cause a DTC P0200 to set and will also cause a misfire due to an inoperative injector. A misfire DTC should also be set indicating which cylinder is inoperative.
    • Long term and short term fuel trims that are excessively high or low are a good indication that an injector is faulty. Use Chart C-2A to check for faulty injectors.

Test Description

The numbers below refer to the step numbers on the diagnostic chart.

  1. This step determines if DTC P0200 is the result of a hard failure or an intermittent condition.

    2.

  2. Tests the harness wiring and for PCM control of the injectors using test light J 34780-2. If the test light is ON steady before cranking the engine as well as while cranking the engine, then the injector driver circuit is shorted to voltage. If the tests light blinks PCM and wiring to the injectors are OK. Chart C-2A will check if injectors are faulty.

    3.

  3. Because the test light was ON steady, voltage to the injector is OK, but the driver circuit is grounded at all times. This step determines if the circuitry is shorted to ground or the PCM is faulty.

    4.

  4. Determines if voltage is available to the injector. Voltage is supplied through the fuel pump relay so the engine must be cranked to see voltage at the injector.

    5.

  5. This step determines if the driver circuit is open or shorted to voltage or if the PCM is faulty.

    6.

  6. Since voltage is supplied to the injector on a single circuit before the injector harness, the fault could only be a poor connection or open in the injector harness. An open before the harness would result in a Cranks But Won't Run complaint.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

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

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Will the engine start?

Go to Step 3

Go to Chart A-3

3
  1. Install scan tool, clear DTC.
  2. Idle engine for 1 minute.

Does DTC P0200 reset?

Go to Step 5

Go to Step 4

4
  1. Ignition ON engine OFF, review Freeze Frame data and note parameters.
  2. Operate vehicle within Freeze Frame conditions as noted.

Does P0200 reset?

Go to Step 5

Go to Diagnostic Aids

5
  1. Engine OFF.
  2. Remove crankcase ventilation oil/air separator for injector access.
  3. Disconnect all 4 injector connectors from injectors.
  4. Install an injector test light on injector connector 1.
  5. Crank engine and note light.
  6. Remove the injector test light and install the test light on the remaining injector connectors.
  7. Crank engine and note light on remaining injector connectors.

Does injector test light blink on all tests?

Go to Chart C-2A

Go to Step 6

6

Note whether injector test light was OFF or ON steady in step 5.

Was test light ON steady while cranking engine?

Go to Step 7

Go to Step 10

7
  1. Disconnect PCM connector for affected injectors.
  2. With a test light connected to B+, probe the affected injector driver circuits.

Does the test light illuminate?

Go to Step 8

Go to Step 9

8

Repair short to ground in injector driver circuit.

Is the action complete?

Go to Powertrain On Board Diagnostic (OBD) System Check

--

9

Replace PCM.

Is action complete?

Go to Powertrain On Board Diagnostic (OBD) System Check

--

10
  1. With a test light connected to ground, probe the ignition feed circuit of the affected connector.
  2. Crank engine.

Is test light illuminated while cranking?

Go to Step 11

Go to Step 12

11
  1. With a test light still connected to ground, probe the injector driver circuit of the affected connector.
  2. Crank engine.

Is the test light OFF while cranking?

Go to Step 13

Go to Step 14

12

Repair open ignition feed circuit in the injector harness.

Is action complete?

Go to Powertrain On Board Diagnostic (OBD) System Check

--

13

Check the injector driver circuit for an open.

Was a problem found?

Go to Step 15

Go to Step 16

14

Repair short to voltage in injector driver circuit.

Is action complete?

Go to Powertrain On Board Diagnostic (OBD) System Check

--

15

Repair open in the injector driver circuit.

Is action complete?

Go to Powertrain On Board Diagnostic (OBD) System Check

--

16

Replace PCM.

Is action complete?

Go to Powertrain On Board Diagnostic (OBD) System Check

--