Nissan Pathfinder/Infiniti QX4 FAQ

CONTENTS
1. Purpose
2. Common problem areas
3. Trouble codes (common codes on the pathfinders are highlighted)
4. Solutions
5. WD21 Specific

Purpose: I am not a pathfinder mechanic or anything like that, the purpose of this FAQ is to provide the members with a decent overview on common problems. What I have done to compile this list is to simply search the Nissan Online Mechanic and Pathfinder/QX4 forum to come up with solutions to certain problems. ALSO, FEEL FREE TO REPLY TO THIS THREAD WITH SUGGESTIONS AS YOU SEE FIT!

Common problem areas
• Intake Cam sensors
• Rear o2 sensors
• P017`1- Air Flow Meter.
• Turbine Revolution Sensor
• HVAC Blower Motor Problems.

Trouble Codes: These are a list of all OBDII codes. The ones placed in bold are codes that are commonly seen on Pathfinders and QX’s

P0000 No Self Diagnostic Failure Indicated
P0100 MAF Sensor
P0105 Absolute Pressure Sensor
P0110 IAT Sensor
P0115 ECT Sensor
P0120 TP Sensor
P0125 ECT Sensor
P0130 Closed Loop, Bank 1 Or Front O2S, Bank 1
P0131 Front O2 Sensor, Bank 1 Lean Shift Monitoring
P0132 Front O2 Sensor, Bank 1 Rich Shift Monitoring
P0133 Front O2 Sensor, Bank 1 Response Monitoring
P0134 Front O2 Sensor, Bank 1 High Voltage
P0135 Front HO2S Heater, Bank 1
P0136 Rear O2S, Bank 1
P0137 Rear O2S, Bank 1 Minimum Voltage Monitoring
P0138 Rear O2S, Bank 1 Maximum Voltage Monitoring
P0139 Rear O2S, Bank 1 Response Monitoring
P0140 Rear O2S, Bank 1 High Voltage
P0141 Rear H02S Heater, Bank 1
P0150 Closed Loop, Bank 2 Or Front O2S, Bank 2
P0151 Front O2 Sensor, Bank 2 Lean Shift Monitoring
P0152 Front O2 Sensor, Bank 2 Rich Shift Monitoring
P0153 Front O2 Sensor, Bank 2 Response Monitoring
P0154 Front O2 Sensor, Bank 2 High Voltage
P0155 Front HO2S Heater, Bank 2
P0156 Rear H02S Sensor, LH Bank
P0158 Rear O2 sensor, LH
P0159 Rear O2 sensor, RH
P0160 Rear O2S, Bank 2
P0161 Rear H02S Heater, LH Bank Or Bank 2
P0171 Fuel System Lean, Bank 1
P0172 Fuel System Rich, Bank 1
P0174 Fuel System Lean, Bank 2
P0175 Fuel System Rich, Bank 2
P0180 Tank Fuel Temp Sensor
P0300 Random Misfire
P0301-P0308 Misfire, Cylinder No. 1–8
P0325 Knock Sensor, Bank 1
P0330 Knock Sensor, Bank 2
P0335 CKP Sensor (Pos)
P0340 CMP
P0400 EGR System
P0402 EGRC/BPT Valve
P0403 EGR Volume Control Valve Circuit
P0420 TW Catalyst System, Bank 1
P0430 TW Catalyst System, Bank 2
P0440 EVAP Small Leak
P0443 Purge Control/V & S/V
P0446 Vent Control Valve
P0450 EVAP Pressure Sensor
P0500 Vehicle Speed Sensor
P0505 IACV/AAC Valve
P0510 Closed TP Sensor
P0600 A/T Comm Line
P0605 ECM/ECU
P0705 PNP Or Inhibitor Switch
P0710 ATF Temp Sensor
P0720 VSS A/T
P0725 Engine Speed Signal
P0731 A/T 1ST Signal
P0732 A/T 2ND Signal
P0733 A/T 3RD Signal
P0734 A/T 4TH Signal Or TCC
P0740 TCC SV Solenoid
P0744 A/T TCC Signal
P0745 Line Pressure S/V
P0750 Shift Solenoid/V A
P0755 Shift Solenoid/V B
P1105 MAP/BARO Switch SOL/V
P1110 Intake Valve Timing Control, LH Bank
P1120 TP Sensor 2
P1125 Tandem TP Sensor
P1130 Swirl Control Valve Control Solenoid Valve
P1135 Intake Valve Timing Control, RH Bank 2
P1140 Intake Valve Timing Control Position Sensor, LH Bank 1
P1145 Intake Valve Timing Control Position Sensor, RH Bank 2
P1148 Closed Loop, Bank 1
P1165 Swirl Control Valve Control Vacuum Check Switch
P1168 Closed Loop, Bank 2
P1210 Traction Control Signal Circuit
P1220 FPCM
P1320 Ignition Signal, Primary
P1335 CKP Sensor (Ref)
P1336 CKP Sensor (POS) Cog
P1400 EGRC Solenoid/V
P1401 EGR Temp Sensor
P1402 EGR System
P1440 EVAP Small Leak
P1441 VC/V Bypass/V
P1443 Canister Control Vacuum Check Switch
P1444 Purge Volume Control/V
P1445 Purge Volume Control/V
P1446 Vent Control Valve
P1447 EVAP Purge Flow
P1448 Vent Control Valve
P1490 VC/V Bypass/V
P1491 VC Cut/V Bypass/V
P1492 Purge Control/V S/V
P1493 Purge Control/V & S/V
P1605 A/T Diag Comm Line
P1705 TP Sensor A/T
P1706 PNP Switch
P1760 Overrun Clutch S/V
P1900 Cooling Fan

Solutions:

Intake Timing Sensors: First, read this thread. http://forums.nicoclub.com/zerothread/116383 . NISTECH, our resident Nissan technician, has listed ways to help clearly diagnose and correct this problem.

Rear O2 sensors: http://forums.nicoclub.com/zerothread/114207. This thread is also very helpful. The gist of this is that the rear o2 sensors commonly fail, and not only do they need replaced, but there is an ECM reflash needed to correct the problem permanently.

P0171: http://forums.nicoclub.com/zerothread/135082. What this thread deals with is a lean condition on one or possibly both banks. What this generally is caused by is the MAF (Mass Air Flow Sensor) going bad. Some mechanics will say that a bad MAF will cause it to read lean on both banks, but this is not always the case. You can read the readings on both banks and often you will find that the other bank is reading lean, but not lean enough to throw a code. New MAF from the dealer or NICO sponsors are around $400, but many people have had good luck with replacing them with used MAFs from wrecked cars.

Turbine Sensor- Often this sensor does not fail, but instead leaks fluid, possibly on other components. Sometimes its been known for the fluid leakage to cause other sensors, such as the o2 sensors and such to fail as well.

HVAC Blower Motor- Sometimes the blower motor will operate only on one speed (usually high) or it will not operate at all. Generally the blower amplifier is the culprit.

5. WD21 info for Pathfinder from 87-95: Main problems.

Frame rust. Even on non-offroaded Pathys, the frame can rust out quite badly from the inside out, particularly in the rear over the wheels and above the gas tank. Tap on your frame with a small hammer or poke it with a screwdriver to see if you have more holes than you should. ALWAYS inspect any WD21 Pathfinder you wish to purchase before buying it in this regard. Other rust-prone areas are directly under the gas pedal on the floor (the catalytic converter is there and sometimes a leak can shoot superhot exhaust at the floor, which rusts it out badly), under the back seats on the floor (poor seam sealing on Nissan's part) and at the tension rod frame mounts up front. Tension rods are the short bars that go between the lower control arm and the frame in the front suspension. The tension rod mounts have a tendency to waller out and/or rust out, which can result in a broken tension rod and the need to re-weld some steel back into the mounts to fix the problem. Tension rods are also called compression rods or strut rods. I recommend using polyurethane bushings to replace stock rubber tension rod bushings whenever possible.

The stock transmission cooler for automatic transmissions needs replacement! On automatic transmission-equipped Pathfinders: failure of planetary gear set and loss of reverse or forward gears: the stock transmission cooler on WD21's is a far cry from adequate. The stock cooler clogs up over time and chokes line pressure to the transmission, which overheats it, reduces lubrication and RUINS the transmission. The stock cooler is located inside the radiator, which has line inlets at the bottom of the rad.

If you are reading this, have an auto 87-95 Pathy and haven't done so yet, GET AN EXTERNAL TRANSMISSION COOLER.

DO NOT USE the stock transmission cooler. Get yourself the largest trans cooler you can find and install that instead. The plate-type coolers work better than the tube-and-fin type. I personally have a pair of 8x11 plate-type trans coolers from junkyard Ford Exploders installed on mine and have had no problems with them to date. They cost me $5 each and took about an hour or so to install in front of the radiator along with some hose clamps, some hose and a neat ziptie-like mounting kit I bought at a local auto parts store for $5. This will prevent the overheating and eventual internal destruction of your transmission.

Thanks,
mgmt.

Quote »

1. REAL mileage a 94 or similar model gets? 2. really no airbags on these? 3. any problems i should look out for or check for when checkin the vehicle out? 4. how reliable and easy to work on are these trucks? 5. whats the aftermarket like for these? I dont want a 12" skyjacker, but maybe a body lift and a SRI and a couple other things here and there, i briefly checked ebay and nothing came up except for clear front signals.

1. Between 12-15 city, 16-20 highway. Mileage was stated at 15/18 when they were new. Depends on engine condition and maintenance. You be better off to test drive one to see if the power output is decent enough for you, if you upsize the tires you're going to lose speed/acceleration real fast. 153 HP, 180 ft-lbs of torque is what they came with new, no idea if that'll last 100K.

2. I think they started putting airbags in on the 96 R50 models and never had any in the US WD21 87-95's. So, no on the airbags AFAIK.

3. Auto transmission problems on so-equipped models. Normal auto shifting is quirky at best and took me a while to get used to, but more serious problems like a missing gear(DO NOT BUY) or slippery shifts (might just need a fluid change, knock on wood) are indicators that something really wrong may be about to happen to that automatic. These things have a history of dying without notice and rebuilds or replacements are NOT cheap. ($1100-2200) If you do find a nice auto that shows no problems, you should immediately upgrade your transmission cooler with a high-flow high-capacity external unit and DO NOT USE the stock cooler. The stock cooler clogs up and kills the transmission.

Lack of power problems is another point to contend with as well as the frame rust issues. DEFINITELY check the rear frame over the wheels and near the gas tank for rust. Poke it with a screwdriver, hit it with a small hammer, whatever it takes, just make sure there aren't holes ready to pop out at you next week. You don't want to deal with cutting the frame up and rewelding a bunch of things under there.

Manual transmissions sometimes wear out and slip, stick or grind between gears. There was a design flaw in the 5-speed manual transmissions: the fill hole for the gear oil was located too low on the case, causing underfilling and preventing proper lubrication for the entire gear train inside. They fixed the design in 1996, but to this day I haven't found anyone that knows that besides a Nissan nut or dealership tech. The manual trans needs an extra 1 liter of gear oil on fill-up. You can do that by jacking it up on one side to tip the truck, or by removing the shifter and pouring it in through the hole up on top.

I'd post more stuff, but I'm getting tired. Those are the main bad points.

Oh yeah...exhaust manifolds leaking...very common, caused by poor exhaust stud material, the studs break and cause the manifold to leak. Usually sounds like a clicking noise at startup that gradually quiets down after driving for a little while. Broken-off rusted studs inside the head can be VERY painful to extract due to their location and the fact that if you mis-drill the hole in the head you can drill into the water jacket and then have to buy a whole new head, but studs that break off outside the head can often be hammered and extracted without drilling. The fix: use 300ZX turbo exhaust manifold studs instead. They used different steel on those.

Steering: have someone else turn the steering wheel back and forth quickly while you watch the steering components move underneath...excessive play or looseness in joints can add up to a hefty steering parts bill at the repair shop, mostly because 99% of the shops are crooked and want you to replace everything but also because the steering on WD21's is weeeeeaaaaak. Main problem is the centerlink design which allows the tie rods to twist torsionally, thereby wallering out the joints on both the CL AND the tie rods. The idler arm will follow suit in short order, then the balljoints. It adds up.

4. Oh, inasmuch as a 13 year old vehicle is, and can be reliable, I find them to be reliable enough with allowances. You're going to start wearing things out and stuff sometimes stops working when you don't expect it to. Switches, guages, starters, O2 sensors, fan clutches, brakes, timing belt and water pump all wear out and give you grief at one time or another. I never had any complaints about unreliability other than what you would expect to need fixing or replacing on a 19 year old vehicle(mine).

Normal metric tools are all that's needed with exception to the front wheel bearing locknut, which needs a special tool to properly remove and install (a Chevy 1/2 ton front wheel bearing locknut tool can be modified to work in a pinch) but otherwise I've never had to buy anything special to work on it with.

5. Poor. I think one company made a short ram intake for the VG30E Pathy but nobody else does(Frankencar). All the Ebay kits are is a cone filter with a MAF plate adapter to bolt it to, might as well just drop a few bucks on a drop-in K&N and be done with it if you ask me. Neither makes much difference. Clear turn signal lenses are about all you're going to find in the way of aftermarket support on body parts except for 4x4 and off-roading-specific parts like rock sliders, winch bumpers light bars and skidplates. Lift kits are available for sure(3" suspension, 4" suspension, 2 or 3" body lift), but your steering will start to fail on you if you beat on it offroad, sometimes even when you're NOT beating on it.