For 1990-2009 cars

### Strategy Based Diagnosis

1. Review the system operations to familiarize yourself with the system functions
2. Perform an engine management Diagnostic System Check.

All diagnosis on a vehicle should follow a logical process. Strategy based diagnosis is a uniform approach for repairing all vehicle systems. The strategy based diagnostic flow chart may always be used to resolve a system problem. The diagnostic flow chart is the place to start when repairs are required.

### Visual/ Physical Inspection

1. Inspect the vehicle for aftermarket accessories which may adversely affect engine operation.
2. Inspect the easily accessible or visible system components for obvious signs of damage or conditions that may cause the symptom.
3. Check the engine lubrication system for the following:

• | Correct oil level

• | Correct lubricant viscosity

• | Correct oil filter application

• | Contaminated or burnt oil

4. Confirm the exact operating conditions under which the fault occurs. Note factors such as:

• | Engine speed (RPM)

• | Ambient temperature

• | Engine temperature

• | Engine warm-up time

• | Vehicle road speed

5. Compare the engine sounds, if applicable, to a known good engine, and ensure you are not trying to diagnose a normal operating condition.

### Intermittent

For intermittent faults, test the vehicle under the same conditions the customer reported in order to confirm whether the system is operating correctly.