There is no omniscient diagnostic machine that you connect and instructs you on exactly what to repair. The closest thing to it is the technician. Using the scientific method they decide what type of testing is needed, review results and make logical conclusions based on research and test results.
1. Best guess method.
The best guess method consists of hooking up a code reader, and reading the codes. Then the technician suggests a repair based on his previous experience. This type of service is usually free but has no guaranteed results.
2. Shotgun method.
The shotgun method is similar to the best guess method. The shotgun method differs in that the technician usually recommends replacement of a numerous amount of parts related to the fault code. This type of service is usually free but has no guaranteed results.
3. Pinpoint method.
Using the pinpoint method our goal is to determine a single repair or single part replacement to solve your problem. When we find the problem we can price your repair exactly to the penny.
The pinpoint method requires that we follow a specific routine:
a) Discuss in detail the symptoms, and under what conditions they occur.
b) Connect scan and data computer and record codes (there are about 3500 P type codes not to mention B, C and U codes).
c) Test drive, verify symptoms and record data.
d) Check Alldata, IATN and bound texts for tech bulletins and repairs related to codes and symptoms.
e) Test as necessary duplicating specific conditions such as speed, road condition, weather or temperature while following manufacturer’s trouble tree steps. This may involve:
1. Pressure and volume testing of fluids and gases.
2. Measuring, plotting and recording electrical data.
3. Measuring temperatures.
4. Removal, inspection and measuring dimensions.
5. Bench testing and actuator testing.
6. Replacement with known good parts.
f) Price repairs accurately.
g) Perform repairs.
h) Test drive and confirm elimination of symptoms.
The diagnostic steps may take about an hour or may take 4 or more hours before any repairs are performed.
Required for pinpoint diagnostics:
a) Code and data scanners: $5000.00 per unit (we have 3)
b) Office personal computer, laptop: $1500.00
c) Repair information, internet (Alldata, IATN): $210.00, $15.00 a month, and $50.00 a month.
d) Digital volt ohm meter: $250.00
e) Electrical load simulator: $350.00
f) Oscilloscope: $1000.00
g) Fuel pressure and vacuum gauges: $350.00
h) Electrical test leads, connectors and lights: $500.00
i) Battery and charging system load tester: $250.00
j) Timing light: $150.00
k) Boroscope: $425.00
l) Vehicle hoist: $5000.00
m) Plus hand tools, rent, insurance and utilities, and employee pay ($don’t ask)!
This service is $50.00-$100.00 with guaranteed results.
Ninety five percent of technicians use best guess or shotgun methods while the knowledgeable, elite technician uses the pinpoint method. Our experience has taught us that if you shortcut diagnostics your conclusions are usually incorrect. Let’s take for example an Autozone shotgun diagnostic of a P410 air pump code on a 2002 Cadillac. They connected a $100.00 code reader and recommended replacing the air pump and relay at a cost of about $400.00. After the repair the check engine light came back on with the same code. We performed a pinpoint diagnostic and repaired a cut vacuum line for a total cost of $79.00.