P1222

Diagnostic Chart:

CIRCUIT DESCRIPTION

The PCM will enable an injector on the intake stroke of each cylinder. Individual cylinder fuel control is referred to as Sequential Multiport Fuel Injection (SF1).

Ignition voltage is supplied directly to the fuel injectors. The PCM controls each injector by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line which is monitored by the PCM. When the PCM is commanding a component ON, the voltage of the control circuit should be (refer to Injectors for schematic) low (near 0 volts). When the PCM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high (near battery voltage). It the fault detection circuit senses a voltage other than what is expected, the fault line status will change causing the DTC to set. The PCM will monitor each injector circuit for the following:

^ A grounded circuit.

^ An open circuit.

^ A circuit shorted to voltage.

^ An injector that is open.

^ An injector that is shorted or has low resistance.

When the PCM detects any of the above malfunctions, a DTC P0200/P1222 will set and the driver will be disabled.

CONDITIONS FOR SETTING THE DTC

^ Ignition voltage greater than 10.0 volts.

^ The PCM detects the wrong voltage potential on any injector driver circuits for less than 0.5 second.

ACTION TAKEN WHEN THE DTC SETS

^ The DTC will be stored in the PCM memory when the diagnostic runs and fails.

^ The Malfunction Indicator Lamp (MIL) will not illuminate.

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

CONDITIONS FOR CLEARING THE MIL/DTC

^ The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.

^ A last test failed (Current DTC) will clear when the ignition is cycled and the diagnostic runs and does not fail.

^ A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

^ PCM battery voltage is interrupted.

^ Using a Scan tool.

DIAGNOSTIC AIDS

^ If an injector is disconnected while the engine is operating and a DTC P0200 sets, the injector driver will be disabled for the entire ignition cycle.

^ When the injector driver is disabled, an engine misfire will be apparent and a misfire DTC will set.

For intermittents, refer to Symptoms. Testing and Inspection

TEST DESCRIPTION

Number(s) below refer to step numbers on the diagnostic table.

3. If the misfire counters do not appear to indicate a specific cylinder, check the injector power feed circuit for an intermittent open. This includes the injector fuses themselves as well as the connections within the fuse panel.

5. If moving the related circuitry does not cause the counter to increment, an injector coil which opens intermittently when hot can cause this DTC to set. Refer to Fuel Injector CCII Test.