P0204

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

Schematic:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) has four fuel injector driver circuits, each of which controls a fuel injector. The PCM monitors the current in each driver circuit and is able to control the driver circuit. The current through each driver can rise to a peak of 2 amps in order to quickly open the fuel injectors. The current can reduce to 1/2 amp to hold the fuel injectors open. This is called peak and hold. If the current cannot reach a 2-amp peak, a DTC is set. This DTC is also set if a fuel injector driver is shorted to voltage.

CONDITIONS FOR RUNNING THE DTC
^ The engine is running.
^ The battery voltage is more than 9 volts.

CONDITIONS FOR SETTING THE DTC
^ The injector current is less than 1 amp.
Or
The injector current is continuously high.
^ The above conditions are met for 7 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The Malfunction Indicator Lamp (MIL) illuminates.
^ The PCM records the operating conditions at the time when the diagnostic fails. This information stores in the Freeze Frame and Failure Records buffers.
^ A history DTC stores.
^ The 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.
^ Use a scan tool to clear the DTCs.

DIAGNOSTIC AIDS
An injector driver circuit that is open or shorted to voltage will cause a DTC P0201-204 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. Refer to Fuel Injector Coil Test - Engine Coolant Temperature (ECT) Between 10-35 Degrees C (50-95 Degrees F) to check for malfunctioning injectors. Component Tests and General Diagnostics

A faulty electrical connection may be cleaned when you are disconnecting and reconnecting the electrical connector. If the malfunction is not present after the electrical connector is disconnected and reconnected, check the electrical terminal connection for the following conditions:
^ Corrosion
^ Faulty terminal tension

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
1. The Powertrain On-Board Diagnostic (OBD) System Check prompts you to complete some of the basic checks and to store the Freeze Frame and Failure Records data on the scan tool if applicable. This creates an electronic copy of the data that was captured when the malfunction occurred. The scan tool stores this data on the scan tool for later reference.
3. This step tests the harness wiring and for the PCM control of the fuel injectors by using the fuel injector test lamp. If the test lamp blinks, this indicates that the PCM and the wiring to the fuel injectors are OK.
4. Whether the test lamp was ON steady or OFF while cranking the engine, this step narrows the malfunction down to just a few possibilities.
5. Because the test lamp was ON steady, the voltage to the fuel injector is OK, but the fuel injector driver circuit is grounded at all times. This step determines if the circuitry is shorted to ground or if the PCM is malfunctioning.
7. This step determines if the voltage is available to the fuel injector. The voltage is supplied through the fuel pump relay so that the engine must be cranked in order for you to see voltage at the fuel injector.
8. This step determines if the fuel injector driver circuit is open or shorted to voltage or if the PCM is malfunctioning.
9. Because the voltage is supplied to the fuel injector on a single circuit before the fuel injector harness, the malfunction could only be a faulty electrical connection or an open in the fuel injector harness. An open before the harness would result in a Cranks But Will Not Run complaint.
10. Check for faulty electrical connections and corroded terminals at the following connectors:
^ The fuel injector electrical connector
^ The fuel injector harness connector
13. Reprogram the replacement PCM and perform the crankshaft position system variation learn procedure. Refer to the latest Techline(TM) information for PCM programming.