DTC 18

Diagnostic Trouble Code (DTC) 18:

Injector Circuits:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) controls each individual injector by providing a ground. The PCM will enable each injector on the intake stroke of each cylinder and is referred to as Sequential Multiport Fuel Injection (SFI).

The PCM continuously monitors the voltage of each injector driver circuit. When the PCM detects a voltage that is out of range, (grounded circuit, open circuit, a circuit shorted to voltage, an injector that is shorted, open, or has a low resistance), a Diagnostic Trouble Code (DTC) 18 will set and the driver will be disabled.

DTC 18 WILL SET WHEN
The PCM detects the wrong voltage potential on any of the injector driver circuits for 4 seconds or more.

ACTION TAKEN (PCM DEFAULT)
The PCM will disable the injector driver on the particular injector that had a fault. DTC 18 will be stored in the PCM memory but will not turn "ON" the Malfunction Indicator Lamp (MIL).

DTC CHART TEST DESCRIPTION
Numbers below refer to circled numbers on the diagnostic chart.

1. The injector fuse(s) are located in the underhood electrical center.
2. Performing an injector balance test is necessary to locate what injector circuit is faulty.
3. Fuse # 18 feeds injectors 2, 3, 5, 8, and fuse # 16 feeds injectors 1, 4, 6, 7.
4. When checking injector resistance, engine coolant temperature should be about 21°C (70°F).

DIAGNOSTIC AIDS
If an injector is disconnected and then reconnected while the engine is operating, the injector driver will be disabled for a predetermined time and a DTC 18 will set. When the driver is disabled, an engine miss will be apparent.