Diagnostic Strategies

Flow Of Diagnosis:

1. Get detailed description of the complaint. Road test the vehicle for verification.
For further description of complaint use DRIVEABILITY WORKSHEET and VEHICLE REPAIR HISTORY forms below.

2. VISUALLY/PHYSICALLY INSPECT THE FOLLOWING:

a. Battery should be fully charged and cable connections should be clean and tight.

b. Electrical wires for proper routing, tight connections, kinks, abrasions, hardness or damage.
Electrical grounds should be clean and tight.
Harness connections should be secure with each electrical wire fully seated in its housing.
Ignition wires for cracking, hardness, proper routing, arcing and carbon tracking.

c. Check for air or vacuum leaks around the intake manifold, exhaust manifold and pipes, as well as the air induction filter.

d. Vacuum hoses for proper routing, tight connections, cracks, kinks, and hardness.
Check thoroughly for any type of leak or restriction.
NOTE: Some vehicle manufacturers incorporate an orifice insert into a vacuum line. Do not mistake as a BB and cut the vacuum line.

e. Verify that all required components are properly installed.

f. Physical condition of components: cracks, corrosion, looseness, modifications or damage.

g. Plugged or capped ports at the base of the throttle body or on the intake manifold.

3. Check Technical Service Bulletins for manual updates, testing procedures, warranty and recall information.

4. Refer to Powertrain Management/Computers and Control Systems/Testing and Inspection/Procedures.

5. Proceed to TESTING PROCEDURES/DIAGNOSIS BY SYMPTOM for the symptom which the vehicle is exhibiting.

Driveability Worksheet:

Driveability Worksheet:

DRIVEABILITY WORKSHEET

Vehicle Repair History:

Vehicle Repair History:

VEHICLE REPAIR HISTORY