P0200

Diagnostic Chart:

Wiring Diagram:

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 called 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 5 seconds.

Action Taken When the DTC Sets

^ The Malfunction Indicator Lamp (MIL) will illuminate.

^ The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.

^ A history DTC is stored.

^ Coolant fan turns ON.

Conditions for Clearing the MIL/DTC

^ The MIL will turn OFF after three consecutive ignition cycles in which the diagnostic runs without a fault.

^ A history DTC will clear after 40 consecutive warm up cycles without a fault.

^ DTC(s) can be cleared by using the 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 injector is inoperative.

Long term and short term fuel trims that are excessively high or low are a good indication that an injector is malfunctioning. Use Fuel Injector Coil Test to check for malfunctioning injectors.

Test Description

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

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.

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

5. Test the harness wiring and for PCM control of the injectors using test light J 34780-2. If the tests light blinks, the PCM and wiring to the injectors are OK. Fuel Injector Coil Test will check if injectors are malfunctioning.

6. Whether the test light was ON steady or OFF while cranking the engine narrows the possible malfunctions down to just a few.

7. 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 malfunctioning.

9. The replacement PCM must be programmed and the crankshaft position system variation procedure must be preformed. Refer to the latest Techline procedure for PCM reprogramming and also refer to Powertrain Control Module for the Crankshaft Position System Variation Procedure.

10. 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.

11. This step determines if the driver circuit is open or shorted to voltage or if the PCM is malfunctioning.

12. Since voltage is supplied to the injector on a single circuit before the injector harness, the malfunction 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.

13. Check the injector electrical connector, the injector harness connector and the PCM for poor connections or corroded terminals.