Engine Does Not Start/Will Not Perform Self-Diagnostics

NOTE:

If the engine does not start and the vehicle will not display codes on the instrument panel lamp, make these basic tests. You will need a wiring diagram of the specific vehicle for some of the checks.

Check The Following

- Battery - Check the battery state of charge and cranking capacity. The scanner draws very little current and can operate with voltage as low as 7.5 volts. Therefore, the scanner may appear to operate normally even it the battery does not have enough power to crank the engine or operate the vehicle computer.

- Controller supply voltage - The engine controller receives battery voltage (B+) through a fusible link. Check a wiring diagram for the location of a fusible link and test for an open circuit. Also check the J1-J2 circuit splice near the controller.

- Controller ground - The controller is grounded to a remote engine ground. This is circuit J9 on most Chrysler vehicles. Use a wiring diagram to identity the location of the ground connection. An open ground can keep a fuel-injected engine from starting. A high-resistance, or "dirty," ground can cause overall poor operation.

An open ground or battery voltage (B+) circuit on a fuel-injected engine will remove power from the system computer and keep the engine from starting. A carbureted engine may start and run even it the power circuit to the computer is open. It probably will run very poorly, however, because it will be running without feedback fuel control or spark advance control.