The term ‘‘intermittent failure'' means a system may have had a failure, but it checks OK now. If the malfunction indicator lamp (MIL) on the dash does not come on or the PGM-FI display does not on, check for poor connections or loose pins at all connectors related to the circuit that you are troubleshooting. If the MIL was on but then went out, the original problem may have been intermittent.

‘‘Open'' and ‘‘short'' are common electrical terms. An open is a break in a wire or at a connection. A short is an accidental connection of a wire to ground or to another wire. In simple electronics, this usually means something won't work at all. With complex electronics (such as ECMs) this can sometimes mean something works, but not the way it's supposed to.

On these models, if you turn the ignition switch to the ON (II) position, without starting the engine, the malfunction indicator lamp (MIL) (A) will come on for about 20 seconds. It then goes off or blinks 5 times under various conditions. This is normal: it shows the self-testing condition of the diagnostics for the diagnostic for the emissions control systems.

If the MIL in the gauge assembly will come on or the PGM-FI (B) in the information display will on, go to how to use the HDS.

If display is on, engine oil level sensor may have had a failure. Connect the HDS to the data link connector (DLC) located under the driver's side of the dashboard. Check the diagnostic trouble code (DTC) and note it. Then refer to the indicated DTC's troubleshooting, and begin the appropriate troubleshooting procedure.

If display is on, engine oil level may have had a failure. Check the engine oil level sensor.

If display is on, do the DPF regeneration.

If display is on, DPF may have had a clogging. Do the DPF regeneration.

When the ECM senses a malfunction in the system, the MIL (A) in the gauge assembly will come on or the PGM-FI (B) in the information display will on.

When the HDS is connected to the data link connector (DLC) (A) (located under the driver's side of the dashboard), it will indicate the diagnostic trouble code (DTC) when the ignition switch is turned ON (II).

If the MIL or the PGM-FI display has been reported on, or if a drivability problem is suspected, follow this procedure:

If the MIL and/or the PGM-FI display does not come on but there is a drivability problem, do the symptom troubleshooting.

Some of the troubleshooting requires you to reset the ECM and try to duplicate the DTC. If the problem is intermittent and you can't duplicate the DTC, do not continue through the procedure. To do so will only result in confusion and possibly, a needless replaced ECM.

The inside ECM stores various specific data to correct the system even when there is no electrical power such as the battery negative terminal or No. 9 IGP (20 A) fuse are disconnected. But stored data based on failure parts should be cleared by using the ‘‘CLEAR COMMAND'' of the HDS, if parts are replaced.

HDS has three kings of clear command to meet the purpose. They are DTC clear, ECM reset. DTC clear command erases all stored DTC codes and Freeze Data. This must be done with the HDS after reproducing DTC during troubleshooting. ECM reset command erases all stored DTC codes, Freeze Data and all specific data to correct the system.

This command clears stored specific data from each vehicle such as DTC and freeze data.

Special Tools Required

Use the procedure when you have to update the ECM during troubleshooting procedures.

NOTE:

Special Tools Required

Use this procedure when you have to substitute a known-good ECM during troubleshooting procedures.

The OBD Status shows the current system status of each DTC and all of the parameters. This function is used to see if the technician's repair was successfully finished. The results of diagnostic tests for the DTC are displayed as: