Limp mode diagnosis….

Geffellz18

Senior Member
Seeking some insight from any pros on here:
2003 Nissan Pathfinder 4x4 w/ 3.5L V6.
Issue is I parked the truck and it sat for a couple of months after taking it down to S. GA for a kayak trip in the Okefenokee.
It’s my off road toy so it doesn’t get driven often at all.
Went to crank it about 6-8 weeks ago and battery was dead-Ends up there is apparently a short somewhere because now if I don’t crank it within 3-4 days the battery dies. It’s a brand new battery.
The primary issue however is that the truck is now in limp mode, but isn’t throwing a code to engage the check engine light. Last time it was the crank position sensor so I changed it and was back in business.
I did run a live scan and there is one issue that continues even though there’s no CEL and it comes back even when I clear it.
P0550-power steering pressure sensor.
My question is will this cause the vehicle go into limp mode?
Also, any best practices for trying to diagnose the apparent short that keeps killing the battery. I have it on a trickle charger now to keep it charged.
 

Donal

Senior Member
Un plug the sensor and see if that eliminates the short. The ecm uses the output from the sensor to control engine rpms sufficient to maintain steering system pressure. replacement switch is sort of expensive, about 120 wholesale
 
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DAVE

Senior Member
Often a new battery will be no good from the start. First thing to do is have battery checked. If battery is weak and the voltage drops below 10v when cranking this can make vehicle go into limp mode even without setting code. I guessing that other issue is the knock sensor which on a Nissan will not turn on the MIL and will not set limp mode or other running problem. That knock sensor is under the intake and is a major job to replace. The power steering switch is to stabilize idle when putting load on system, I don't know if it will set limp mode but probably not.
 

transfixer

Senior Member
Seeking some insight from any pros on here:
2003 Nissan Pathfinder 4x4 w/ 3.5L V6.
Issue is I parked the truck and it sat for a couple of months after taking it down to S. GA for a kayak trip in the Okefenokee.
It’s my off road toy so it doesn’t get driven often at all.
Went to crank it about 6-8 weeks ago and battery was dead-Ends up there is apparently a short somewhere because now if I don’t crank it within 3-4 days the battery dies. It’s a brand new battery.
The primary issue however is that the truck is now in limp mode, but isn’t throwing a code to engage the check engine light. Last time it was the crank position sensor so I changed it and was back in business.
I did run a live scan and there is one issue that continues even though there’s no CEL and it comes back even when I clear it.
P0550-power steering pressure sensor.
My question is will this cause the vehicle go into limp mode?
Also, any best practices for trying to diagnose the apparent short that keeps killing the battery. I have it on a trickle charger now to keep it charged.

try another scanner, if you're using one of the small plug in code readers they don't always pull all the codes in the system, since you mentioned the vehicle sat for a couple months, do a visual inspection of the wiring, under the hood and at the back of the engine where the harness goes down to the transmission, look for exposed wiring or wiring chewed into, I've seen squirrels, chipmunks or other rodents chew into wiring when a vehicle sits a while, and Nissan is one of the manufacturers that use wiring with insulation they like, Ford also uses wiring like that, or used to at least up through the early 2000's,

to my knowledge that code would not cause any limp mode issues, I'm betting its a wiring problem, I had a Nissan pickup around the same year come into the shop a few months back with a no shifting issue as well as a couple other symptoms, that ended up being a couple wires chewed in two and three or four others almost chewed in two .
 

Geffellz18

Senior Member
Thanks all for the replies.
Was able to get underneath the truck for a little bit today before I burned to death!

So, yeah I’d say that the Power steering pressure sensor is faulty, ?.
Basically hanging together just by a small piece of the circuit!
3E013E8A-4241-4FDC-8E20-391FAAD90916.jpeg

So, cranked up the truck and the CEL was actually on. Same code but had additional details that wasn’t populating initially.
This time, it referenced shorting-so I’m crossing my fingers that it’s what is causing the short.
0DD7A994-61E7-4F6F-BF33-41F1EF6329A0.jpegC8BB6EFA-FEBE-4FC6-9361-B35F22E35F78.jpeg864ACB59-B2DB-42D1-929E-EA4211F70EEC.jpeg1D6B77D1-AE63-4002-A7EB-FB2A3A130C56.jpeg

I did try to look for potential issues with rodent sabotage but I did not see any evidence of this although there could be an issue I cannot see. We do have a good number of chipmunks and squirrels around the house and I had it parked near the ivy where them rascals like to reside!
I have unplugged the sensor and have taken the trickle charger off to see how the battery does over the next few days with holding a charge.

I’m hoping this is the simple fix I’m hoping for. Like I said, I drove it nearly 700 miles round trip in February with no issues before parking it.
Will know for sure when the replacement comes in.
 
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transfixer

Senior Member
If that circuit happens to get power from the same place the transmission range sensor or the transmission itself does, it may well be the cause of the limp mode ? I'd have to study a wiring diagram to see if that is the case, at this point you're heading in the right direction, change the sensor and see what happens,
 

Geffellz18

Senior Member
So, a somewhat possible promising update. Let the truck sit for a week off the trickle charger with the sensor unplugged and it cranked right up! Hopefully that was the cause of the short.
OEM Replacement sensor ordered…Contacted the dealer and they were outrageous compared to online for same part.
Hopefully the replacement corrects the limp mode issue! Will know for sure by the end of the week.
 

Geffellz18

Senior Member
Got the new sensor installed and its still in limp mode but the short seems to be cleared up since it sat nearly 2 weeks with me checking it just one time about 6 days in. I feel fortunate about that!
Put the code reader on it and still get the same code as referenced above. Guessing that’s the cause for the truck staying in limp mode. Cleared the code and it comes right back.
Kind of at a loss on this now. Anything else I should look at in regards to what’s causing the code? I understand that the new sensor could also be faulty.
I did check fuse boxes to see if any referenced that circuit but found nothing that made sense to me.
Thanks!
 

transfixer

Senior Member
If the same code as before is coming immediately back after replacing the sensor, then there is still an issue with either the connector itself,,( which is possible ) or back up that set of wires there is a break or one of the wires is bare and touching something else, or the other wire ? The only way to check that really is a print out of the ecm connector to see where those wires are at the ecm, and check for continuity from the ecm down to that plug in connector at the sensor .

You might take a test light and with the ignition on check each fuse individually to see if one is blown that is powered up when the ignition is on, if that sensor goes through a fused circuit its likely that fuse is blown, only way to find it will be with a test light or physically pulling each fuse and visually checking them
 

Dusty Roads

Senior Member
Seeking some insight from any pros on here:
2003 Nissan Pathfinder 4x4 w/ 3.5L V6.
Issue is I parked the truck and it sat for a couple of months after taking it down to S. GA for a kayak trip in the Okefenokee.
It’s my off road toy so it doesn’t get driven often at all.
Went to crank it about 6-8 weeks ago and battery was dead-Ends up there is apparently a short somewhere because now if I don’t crank it within 3-4 days the battery dies. It’s a brand new battery.
The primary issue however is that the truck is now in limp mode, but isn’t throwing a code to engage the check engine light. Last time it was the crank position sensor so I changed it and was back in business.
I did run a live scan and there is one issue that continues even though there’s no CEL and it comes back even when I clear it.
P0550-power steering pressure sensor.
My question is will this cause the vehicle go into limp mode?
Also, any best practices for trying to diagnose the apparent short that keeps killing the battery. I have it on a trickle charger now to keep it charged.
Did you clear the code with the headlights on then disconnect the battery?Try that
 

Dusty Roads

Senior Member
Also,your reader might not be capable of a more comprehensive test-Have a AutoZone close by?
 

transfixer

Senior Member
Did you clear the code with the headlights on then disconnect the battery?Try that

He's got an issue with the circuit,, I've sent him a couple of diag charts to follow, that sensor uses the same ground circuit that the tcm does,, so that would explain his limp mode,, likely going to be a corroded or bag ground connection or problem with the ground wire on that circuit.
 

Geffellz18

Senior Member
First, I would like to thank @transfixer for helping me with trying to diagnose the issue with the Pathfinder. Heck of a guy to provide his support like he has! Thank you Sir!

So the truck is still in limp mode, but with the diagrams he sent, I was able to at least troubleshoot even more and possibly eliminate some reasons in hopes to move on to other potential causes.
So today, I tested all of the fuses under the hood and in the cabin. All showed current except one-the starter fuse. I pulled and checked it and it was fine. Even cranked right up with it pulled. I guess it’s one that truly only has current when the starters engaged? Not sure! I went ahead and put a new one in anyways.
So ultimately no issues with the fuses.

Secondly, I tested the connection for the actual power steering sensor following my interpretation of the guidelines outlined on the diagrams. I took pics to verify, but all seem to be somewhat inline with the diagram specs for when the engine is running and wheel turned.
Although I do admit I have no idea what the initials means for wire colors since they don’t seem to match the actual colors I see.

First port checked had the blue wire running to it: 5.08. Color listed as R/B on the diagrams. Range 0.5-4volts
The middle port had the red wire running to it: 0.2-0.3. Color listed as B/P on the diagrams. Range ~0volts
The last port had the black wire running to it:
0.2. Color listed as L on the diagrams. Range ~0volts.
3829A3E0-6DA0-4DC9-A397-09B4F5AB806B.jpeg
2902FF27-DB6A-4076-B7A9-D9CB6B42FC06.jpeg29FF43A7-A9F3-4549-9455-9B34130F5E57.jpeg

I’m no mechanic and certainly could be interpreting this entirely wrong too, but that’s the readings and my interpretation of which wire is which.
Lastly, I did follow the wiring from the connection with the sensor to the first joint connector. The wiring appears to be intact the entire way with no exposed wiring or perceived tampering with the wire loom covering. At the connection point just before it goes into the main connection, there is a small exposed Black/red wire that appears to come from the series of wires that lead to the power steering sensor. I unfortunately cannot follow it to see where it leads to, but it is not very long at all and I believe it’s designed to be exposed like that and there were no signs of any issues upon inspection of the section I could see.
Once the wiring goes into the main connection point, it’s pretty much lost in the shuffle because it’s all covered in larger wire loom and tape sealed.
I did run another series of wiring to the TCM sensor which confirms that both sensors are on the same circuit as well.
Checking the codes, the same code continues to pop back up. No change there.
That’s were we are at in this saga until additional time permits.
 
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transfixer

Senior Member
I have run into wire colors on the vehicle not matching the colors on the diagrams fairly often, not sure why that happens . but if I'm understanding your readings correctly I believe you have a bad ground, did you check the two ground wire connections that are shown in one of the pictures of the chart ? that picture makes it hard to tell where those are located, if I were you I'd check each and every ground wire that is bolted to the engine block or frame, remove each one and clean the connector end with a wire brush or piece of sandpaper and also clean the spot it bolts to, then reconnect and tighten each ground. A bad ground can cause all sorts of weird issues , we see it fairly often at work.
 

Geffellz18

Senior Member
I wasn’t able to locate those identified in the schematic, but found two on the passenger side that I just cleaned off per your advice. One was right on the passenger wheel tub that came off of what looked to be the primary wiring for the vehicle.
I will try to locate them again, taking some of the connectors loos to see a little better, as well as take your advice to locate as many grounds as possible and clean them too.
1AC80020-9F56-4D62-9FB8-C00E043D9A9E.jpeg
72163C64-D742-41C0-B5D3-7A3268A2BD24.jpeg
 

DAVE

Senior Member
I would check black wire with connector disconnected for continuity to body ground which is normal and also check for short to power which is not normal, if that is ok. Go to next step. The power steering switch is only an off and on switch, you know you have proper supply voltage on blue wire #1 terminal, next connect switch and check for a voltage between 1 - 4 volts on middle wire that is red with someone turning steering wheel, this will verify switch is good. If these check good and if you have not already done this you need to check continuity from ecm to red wire at connector. If all this checks normal, next step is unplug tcm and see if code resets. ( Don't discount that your new switch may be faulty).
 
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