speedo + ABS + 4WD not working

[Dlyle]

Hi, new to this group.I couldn't find a similar problem in search.
I have an '02 path w/3.5L V6, auto trans w/4WD, 170K miles. Bought used in good condition primarily to be a 2nd vehicle for backup. It doesn't get driven much. The problem I'm having involves the instrument cluster. Recently we were out looking at Christmas lights and everything was working fine. A week later I used it to run errands and I noticed the speedometer was not working. Also at the same time the ABS fault light came on, the 4WD wheel indicator went out & the 4WD fault light came on. The odometer shows vehicle mileage up to that point, however no new miles are registering. This happened once before. It was summer time and I was looking for a store that wasn't easy to find. After a couple of U-turns, I decided to stop at a gas station and ask. Up to that point everything was working fine. When I got back in & restarted the engine I noticed as I pulled out onto the roadway that the speedo was not working. I drove the 1/2 mile to the store & parked. I figured I would check fuses when I came out of the store but I forgot. When I took off, I noticed everything was working again & had no more problems til now. Don't know if there's any relation but a while ago the engine had a misfire. It went away on its own just as I was dropping it off at the garage for service. Needless to say the garage couldn't find anything wrong, so we had new plugs put in. The misfire has since come pack & the engine light is on. I took it by the garage & they said the spark plug coil on cyl 4 is bad. We haven't been able to get it repaired just yet.
The only other problem we have had is that recently we had an ice storm making the roads slick. My brother-in-law used it to get to work and used the 4WD. When I went to use vehicle later it was in 4LO with the switch in "auto". I tried to drive it on dry roads thinking it would switch on it's own. When it didn't and I couldn't switch it manually I pulled over & read the manual. I followed the instructions in the manual & everything seemed fine after that.
Sorry this is so long but I figure the more info I give, the better someone might be able to help.
Any ideas???

[Dlyle]

Sorry, meant to include that the rest of the gauges (tach, fuel ,temp) & fault lights seem to be working okay.

[Mark Mellott]

I don't know quite where to begin with this one. I have the same Pathfinder except it is the SE model. With everything you described, there is a good chance you have some short and/or open curcuit issues going on. The PCM (the bain of the car) will throw out errorneous toruble codes (check engine light comes on) and cause erractic behavior of many system components if the PCM is damaged or even if the cable to the PCM is not fully plugged or short circuited because the cable connector plug contacts are very dirty. The PCM on your Pathfinder is located up and to the right of the accelerator pedal. Have this looked at to be sure it is intact.

[Dlyle]

Thanks I'll look into that. I'm hoping it'll be as simple & inexpensive as something like that

[NismoPick]

Sounds like the speed sensor, wheel sensor, or ABS controller. The "PCM" or "ECU" controls the engine.

[4xq]

My money is on the speedo - I would have that looked at first. Most common problem would probably be the sensor, but could be wiring or gauge cluster.

Without looking at the service manual, I am guessing the ABS and 4WD systems are failing some kind of sanity check because they are not receiving speedo input, and the warning lights then get lit.

For instance, the speedo is saying 0 mph, since it is not working, but the ABS still senses that the wheels are moving from the wheel sensors.

With a little luck, it shouldn't be too expensive to fix.

[Dlyle]

According to the instrument cluster wiring diagram in my repair manual the speedo, ABS light & 4WD light are enabled by their own control units and all seemed to be enabled by speed sensor input from something called the "Unified Meter Control Unit" which appears to be an integral part of the instrument panel circuit board, but none seemed to trace back to the PCM.
Just for the hell of it, the other day I tried using the cruise control on the freeway. As was expected, the Cruise system is operational, however with no speed info, a cruising speed could not be set. Cruise control is also enabled by the UMCU. So it seems more & more likely that either the VSS or UMCU is bad or there is a loose or corroded electrical connection.

[gcjazz12]

did you figure out a solution to this problem?

[Dlyle]

We're still working on this but here's what we have figured out so far: According to a Nissan tech in another forum the 3.5L V6 models with full time automatic 4WD systems will display the 4WD fault if there is a fault with the ABS system. As for the ABS system My Brother-in-law was checking the oil & antifreeze in his Ford truck and he decided to check the Pathfinder while he was at it. When he opened the hood he got quite a surprise. Apparently during the cold weather in December a rodent (squirrel we believe) was building a nest in the engine compartment right over the right strut mount. It had torn up a significant amount of insulation from the hood. It had also chewed a couple of vacuum lines causing the engine to run rough. It has also chewed most of the wires in the harness to the ABS controller & cruise control vacuum pump/actuator unit. We cleared the nest out once, but it came back a few days ago and chewed a couple of ground wires causing the fuel pump not to work. I have repaired that and got the vehicle running again, but I haven't finished with the ABS wiring yet. Last night it apparently came back and chewed even more wires in the ABS harness. Luckily the ABS harness is up at the top where I can get at it easily to make the repairs. I just haven't had enough warm days to get out there with the soldering Iron & piece in jumper wires. After getting it running again, we moved to a different spot, put a drop light and an electronic pest repeller under the hood. We also got animal repellent that sprinkled around the inside of the engine compartment & on the ground around the vehicle. Hopefully this squirrel (or whatever) will give up and go away. Now that we've declared war, I'll let you who wins.
"Hey Rocky, I told you not to get us a house on wheels, somebody went and moved it away"

[forlon4]

does anyone know the fix to this I have exactly the same thing happening also at 170000 k. Help please?

[gcjazz12]

I had a loose ground to ABS and dealership fixed for $5.99 + diagnostic