Tools - Fault Codes When Using the Multi-Use Tester

9215mitsubishi01

NO.: TSB-92-00-001

DATE: January, 1992

MODEL: All Vehicles Capable of Using the MUT


SUBJECT: VERIFYING FAULT CODES WHEN USING
THE MULTI-USE TESTER (MUT)


PURPOSE

This Technical Service Bulletin describes a procedure to find out if fault codes that appear during MUT testing indicate current or previous vehicle system malfunctions.

AFFECTED VEHICLES

All which can be diagnosed using the MUT.

DESCRIPTION

Fault codes are triggered when any one of several electronic control units in the vehicle senses an abnormal condition in its operating circuitry. This abnormal condition does not always mean that a component has failed. Sometimes, just a loose wiring harness can cause a fault code to be stored.

Also, a fault code may or may not cause an indicator light to turn on, depending on the design of the vehicle system. And, some systems may continue to burn an indicator light even after the condition is corrected. For example, on vehicles equipped with an SRS air bag system, the SRS warning lamp will not go out unless all fault codes in memory are erased. To erase fault codes, the MUT must be used. They cannot be erased by disconnecting the battery.

To fully understand why fault codes are stored and how they will affect the indicator lights on the instrument panel, refer to the troubleshooting sections of each service manual.

Remember, if you see a fault code displayed on the MUT, it doesn't always mean that the vehicle component in question needs replacement. Do not replace components until the cause of the fault code is determined.





To help you verify the presence of a vehicle system malfunction when a fault code is displayed on the MUT, follow the procedure shown.