Well I have somewhat the same issue. 2001 rodeo ecm will not read to obd all wiring and connections are good no bad fuses runs and drives great but will not pass obd2 test will not connect with ecu in

The OBD (On-Board Diagnostics) system in a 2001 Nissan Pathfinder is powered by the vehicle's battery and is controlled by the Engine Control Module (ECM). If the OBD port isn't lighting up your reader, it could be due to a blown fuse.

In your Pathfinder, the OBD fuse is located in the fuse box under the dashboard on the driver's side of the vehicle. The fuse you need to check is the 10A fuse labeled "ECM" or "ECU". You can consult your vehicle owner's manual or the fuse box cover for the exact location of the ECM fuse.

If the ECM fuse is intact, there may be a problem with the OBD system itself or the wiring connecting it to the ECM. In that case, it's best to have a qualified mechanic or technician diagnose the issue to prevent further damage to your vehicle.

ISUSU? no
must be 12,000 miles away down under?
a HOLDEN car, you never told makers name,
wrong fuse size, only use correct size.
the ECU can short easy if CAPS inside short and 2006 to 8 was a bad year for caps. called he CAP Plague
so unplug ECU and see if fuse holds
can be bad wiring, harness.
or damage from rodents. ROO'S? LOL
seen vast ecu short me, for sure 1995 to 2010.
caps go bad. electrolytic type. the leak, split open or explode too.
some only short as car hits bumps, never fun this\
hey good luck downunder ! it's 100f here.

rodeo or rodeo sport.?

log in to mitchell diy and read a bother?

if the windows work then CB15 and CB21 are good
recline and slide motors in seat , both driver and passengers dead
and all modes, slide and recline.
there are 4 motors. if all 4 were dead CB21,feed suspect
or bad ground. there is only one ground B6

if only one fails then only it is bad. (or the switch driving it)
we check voltage to the failing motor, first.
if good the motor is bad or seat is jammed
if motor groans , it may be only jammed.
we cant hear it , or check voltage, only you.

no engine stated. ouch....
all else work? car drives, no mifire????
no low MPG?
no CEL lamp glowing driving,?????? check engine light,.??
if the cluster TACH (stock ) is dead.
then its bad, or the wires from it to the PCm. are bad.
of other cluster gauges or lamps are dead, the fuse blew to the cluster.
that is all i can do working blind, id have to see all to tell all.

ill get your custer drawings and look for you, you can too at Mitchells DIY'
there is 2001 rodeo and rodeo sports. ill guess non sport.

ok the PCM if you scan it and RPM reads ok then all that is ok
the PCM on this car sends RPM data , on 1 wire to the techo,
if it arrives there, (wires) then the tacho works if and only if it has power, if the coolant gage works that means tacho has power too. as they sit on the same power rail in the head.

what are the fault codes reading first
If you feel that the ECM has a problem in itself and not reacting to a faulty sensor get a known good ECM and swap it out as a test

old post
" ecu wont read bur" ><<<< i can not decode this.
bur, vur,nur, byr,bir, nah, bue, but, ah its BUT? (type analysis, me bad)
ECU won't read ,but fues is good, (test fuse, never just look)
What does wont read mean. by what tool by what actions, by you.?
IF the ECU will not scan with a new scan too the fuses are blown.
period! (or wrong scan tool;) this year is VPW OBD2. (ask)

simple answer, alldata.com RTM.
long answer.
we cant answer on any car lacking engine size (type) and country.
sorry. can't. and be RIGHT.
in uSA its 3 engine this year.
2.2 L I4
3.2 L V6
3.5 L V6 each can be quite different, post engine.

Generics.
horn don't blow can be blown fuse. test them. the one marked HORN being first.
can be bad horn relay or bad clockspring. or even a bad horn
to test any horn, HOT wire it. to any 12vdc battery.

ECU issues, gee, what country and engine and what are the Symptoms of your ECU. in details. running or not.
hot or cold, driving or not.

P0135 bank 1 sensor 1 open or short in wires,bad connections,bad sensor ,or bad ecm. P0141 bank 1 sensor 2 same diag as P0135. P0420 cat below threshold open or short, or faulty Ho2s sensors.you may have several problems. start with sensors circuit if good change sensors if not trace to ecm if reading not right replace ecm if all good replace sensors clear codes retest drive two drive cycles for cat to clear tests. then with no dtcs present test fuel pressure , injectors,then ignition system ,timing valves ,map,maf sensors,throttle sensor,crank sensor cam sensor, compression.

The only reason I have ever seen for a dead OBDII or DCL while the car still runs is that the ECM has failed and for some reason just marginally functioning enough to appear normal. This is more common than one would think.

I would start by getting even a generic OBDII reader to confirm your work, then pull the battery connections and unplug the ECM from the harness and make sure visually that the conector has no obvious issues then reassemble and retest.

that usually means that the fuse for the DLC port is blown. if you check your owners manual look for fuses labeled AUX, CIGAR, DATA, DLC. it is usually one of those that the DLC is fused through. i encounter this frequently as i do emissions inspections. check the fuses and you should find the culprit there!

The sending unit in your tank is bad replace it.