Time-Consuming Problems:

Common scenarios which often require more than one hour of diagnostic time:

• Intermittent problems: can be difficult to duplicate. See the PHAD policy on intermittent problems.
  
• CAN Network & Communication problems: since there can be literally dozens of modules on one network, a communication problem can be very time-consuming to pinpoint, especially if the modules are hard to access for testing.
  
• Parasitic battery draws, shorted/open wires in harness: can be time-consuming to track down, especially if interior or exterior panels have to be removed for proper access.
• Aftermarket accessories: alarm systems, remote start, snow plow/brake controllers, lighting, tuners etc. may be interfering with stock vehicle operation.
• Improper previous repairs: faulty aftermarket components, improper harness routing, splicing, etc. may have to be repaired before the actual diagnosis can begin. Sometimes correcting improper repairs solves the initial problem!
• European vehicles: are generally more complex and require more disassembly to access components and wiring. European OEM information and wiring diagrams are at times difficult to obtain and use.
  
• Rare or classic vehicles: as with European makes, proper information (diagnostic procedures, wiring diagrams, etc.) is often difficult to obtain for classic or rare models.