The strategy based diagnostic is a uniform approach to repair all Electrical
and Electronic (E/E) systems. Use the diagnostic flow in order to resolve
an E/E system problem. When repairs are necessary, the diagnostic flow is
also a starting point. The steps below are defined in order to instruct the
technician how to proceed with a diagnosis.
Verify the Customer Complaint
In order to verify the customer complaint, the technician should know
the normal operation of the system.
Preliminary Checks
Perform the following steps:
| • | Conduct a thorough visual inspection |
| • | Review the service history |
| • | Detect unusual sounds or odors |
| • | Gather diagnostic trouble code information in order to achieve
an effective repair |
Check Bulletins and Other Service Information
This should include videos, newsletters, and other available service
information.
Service Information System Checks
One or more DTCs may not support a system. System checks verify the
proper operation of the system. This will lead the technician in an organized
approach to diagnostics.
Service Diagnostics (Paper and Electronic)
| • | DTC Stored - Follow the designated DTC Table exactly in order
to make an effective repair. |
| • | No DTC - Select the symptom from the symptom tables. Follow the
diagnostic paths or suggestions in order to complete the repair, or refer
to the applicable component/system check. |
| • | No Matching Symptom - Analyze the complaint. Develop a plan for
the diagnostics. Utilize the wiring diagrams and theory of operation. |
| • | Intermittents - Conditions that are not always present are intermittents.
In order to resolve intermittents, perform the following steps: |
| - | Observe the history DTCs, DTC modes, and the freeze frame data. |
| - | Check Bulletins for similar cases where repair history may be available.
Combine the technician knowledge with efficient use of the available service
information. |
| - | Evaluate the symptoms and conditions described by the customer. |
| - | Use a check sheet or other method in order to identify the circuit
or electrical system component. |
| - | Follow the suggestions for intermittent diagnosis found in the
service documentation. |
| - | Use a scan tool along with a digital volt meter (DVM) which has
data capturing capabilities that can assist in detection of intermittents. |
| • | Check service bulletins for similar cases where repair history
may be available. Combine technician knowledge with efficient use of the available
service information. |
| - | The condition described by the customer may be normal. Verify
against another vehicle that is operating normally. |
| - | The condition may be intermittent. Verify the concern under the
conditions described by the customer before releasing the vehicle. |
Re-Examine the Complaint
If a technician cannot successfully find or isolate the complaint, a
re-evaluation is necessary. Re-verify the complaint. The complaint could be
an intermittent or a normal condition.
Repair and Verification Tests
After isolating the cause, make the repairs and verify that the concern
has been corrected. Verification may involve road testing the vehicle.
