It might be time to think about shopping for a scan tool.
Vehicles:
2000 Toyota Solara
2000 Chevrolet Impala LS
Been using Autozone for a free scan or relying on a dealer. Not sure if a Laptop based tool is even wise to consider. Definitely want it to be able to do CAN (newer systems) in the future.
I know tools that do ABS is problematic and probably not necessary. Reading parameters might be. History codes probably are useful.
The problems I've had:
2000 Toyota
Oxygen sensor, two occaisions. Middle of winter. Dealer handled. Definatey an easy job. Didn't know about Autozone.
2000 Impala
EVAP codes (gas cap gasket - Autozone)
MAF sensor (new sensor lasted a day and resulted in a no start problem: Engine seemed to catch and would die when ignition released. Pushing on gas pedal would cause engine to run really really rough. (Auozone)
Both problems were related an somewhat intermittant.
Intermittant TPS, TPS signal low - Not a diagnostic code, but rather it was in history. Resulted in car in a no start condition. Cranked OK. Car was scanned by a good samaritan, but he didn't find a code. Resulted in being towed to dealer. Found out that the other dealer must have not put the throttle position sensor connector on correctly (they pulled engine to replace valve cover gasket about a year ago) and/or a cracked connector housing caused water or heat to cause issues. There was no sign of corrosion or a non tight fitting connector.
I also found one nut missing on the EGR hose and a nut missing on the throttle body. Again, probably from when the pulled the engine. It was 100+ degrees the day it failed.
I fixed the nuts and put hi temp (200 C) Silicone self-fusing electrical tape to fix the connector. I'm satisfied with the repair, but mom isn't. The TPS is about $40-$70 from Rock Auto.
So, I guess what I'm saying is that I potentially have more time on my hands to fix things and I seem to have to do the diagnosis anyway. It didn't make sense to tow it home although they had the car 4 days since it occurred on a Friday afternoon.
Any ideas? Actron seems interesting to consider.
You know my experience from installing car AC systems from a box, to rebuilding a 1982 import carb, replace a clutch and/steering rack and any automotive electrical problem.