What should I look for with my OBDII when purchasing a used 4runner?

[questioner]

I am looking to purchase a used 4runner (2003, v8, 150k). I have an OBD2 device that I can sync with my iphone and on an app (DashCommand) I can read out literally anything while the car is driving.
I know toyota is generally a super reliable brand, however what should I be looking for in particular when I have the obd2 hooked up and am taking it for a test drive?

Is there anything in particular that I could monitor that might explain a common major problem?

How can I make sure that none of the brake calipers are frozen up or damaged?
(I have to drive the car back 11 hours if I get it)

Thanks!

 

[MikeInNH]

If the CEL isn't on then I don't see what good the OBDII reader is going to do.

 

[Mike W]

If the CEL isn't on then I don't see what good the OBDII reader is going to do.

Modern OBDII scanners can actually display "pending" codes. Pending codes are codes that, as quoted from a website:

OBD II Pending Codes are also referred to as “continuous monitor” and “maturing codes”. An intermittent fault will cause the computer to store a pending code in memory. If the fault does not recur within 40 warm-up cycles, the code will be cleared from memory. If the fault recurs a specific number of times, the code will then mature into a diagnostic trouble code (DTC) and the MIL or “check engine” light will turn on.

I have had pending codes display on my '05 Accord and '06 5.9 Cummins before via an UltraGauge I use but never trip the CEL

To the OP: Just watch temps, voltages, pressures, etc. If you see anything odd on your OBDII readout make note of it. I am unaware of what all parameters can display on these 4th gens as I will be purchasing one in the next 3-4 months after I sell my Cummins. Best of luck

 

[gshadow325]

If the CEL isn't on then I don't see what good the OBDII reader is going to do.

a GOOD obd2 ready will check the vehicle is readiness state.

when it is ready, that means vehicle went thru drive cycle and nothing has been recently cleared to hide the fact it has a prblem. like bad o2 sensors, bad catalytic converters, leaking manifolds, abs sensors bad, etc.

this is a snap shot of my torque app checking my own vehicle

 

[slyfox75]

I think most of the stuck calipers(the majority) are northern states that get salted in the winter. Most southern 4Runner are "ok" unless maybe they are always in the water. So are you in LA, Cali or Louisiana? It just says "LA" on your profile.
Look at carfax......many stuck calipers show up if they were replaced at dealership.
I wouldn't NOT buy it based on that. Calipers are cheap and easy to do at any shop(or yourself).

I'm owner of 155k+ "southern" 4Runner w v8(2005 4wd).
Only thing I have issues with is:
-cracked dash
-smog pump(AIP) that died on me......which you won't have on an 03. (There is a cheap mod to bypass the whole system anyway)
-Ripped Inner CV boots on both front drive shafts~150K....both happened on SAME road trip.....talk about repeatability

O2 sensors are still kickin, cats are fine, wheel bearings are good, etc, etc.
You'll wear out the interior before the drivetrain on these things!!!!