[Frontier04]

I replaced my old 91 hard body with a frontier, here's my story:
TRUCK: 2004 Frontier 4 cyl, A/T, 38,000mi (YES, THIRTY EIGHT THOUSAND MILES, carfax verified)
When I purchased this truck I knew it had issues, first, a busted radiator (1st thing I replaced), then, the truck is in a limp mode, it won't go past 2000 rpm and the transmission also does not respond: no reverse, no neutral (it moves forward when in it), 1st and 2nd gear sometimes engage and sometimes not, Overdrive is the only constant; But I don't know if all these have something to do with the truck being in limp mode or not, my first concern is to get it out of that mode, and here is where I need your help. SO far I've done the following:
- Cleaned the MAF sensor, throttle body, and its surroundings
- Inspected the air and fuel hoses for leaks and damage and found no apparent issue.
-Then I checked the electrical wiring connections at the sensors, I even checked the throttle position sensor wires for continuity, voltage and grounding and found they work within its limits, finally I have a VCDS scanner which I previously bought to work on my VW and used to scan the truck using the OBDII mode, this is what I've got:

VCDS Release 908.1: Generic OBD2
Mode 1: Read Data
03: Fuel system 1/2 status Closed loop, using O2 sensors
04: Calculated load value 22.7 % (9.5-34%)
05: Engine coolant temperature 74 °C (supposed to be between 75 and 85 degrees)
06: Short Term Trim - Bank 1 -3.1 % (????)
07: Long Term Trim - Bank 1 0.0 %
12: Engine RPM 825 /min (little high, specs call for 750 +/- 50 rpm)
13: Vehicle speed 0 km/h
14: Ignition timing advance for cyl #1 20.0 Degrees (20+/-5 BTDC)
15: Intake air temperature 19 °C
16: Mass Air Flow 5.04 g/s (0.9-5-8 g/s)
17: Throttle position sensor 0.0 %
19: Location of O2 sensors B1S1 B1S2
20: Bank 1 Sensor 1 Status 0.110 V -7.03 %(lean) (????)
21: Bank 1 Sensor 2 Status 0.270 V
28: OBD Requirements Met OBD II (CARB)
33: Distance travelled with MIL on 1 km
Number of DTCs stored: 0 -- MIL Status: MIL OFF
Misfire monitoring: Passed
Fuel System: Passed
Comprehensive Components: Passed
Catalyst monitoring: Failed or Incomplete
Heated catalyst monitoring: Not installed.
Evaporative system monitoring: Failed or Incomplete
Secondary air system monitoring: Not installed.
A/C system refrigerant monitoring: Not installed.
Oxygen sensor monitoring: Failed or Incomplete
Oxygen sensor heater monitoring: Failed or Incomplete
Exhaust Gas Recirculation: Failed or Incomplete

Having found no DTCs stored or pending to know at least where to start (Thought the VAG scanner could not read the CPU completely) , I went and got a CEN-TECH scanner at Harbor Freight and again scanned it to find a DTC, the results were even more unclear, majority of test were "not supported or stored data".
I searched for these topics in the forums to get an idea where to continue to get the truck out of the “safe mode” and found some posts with similar situations, even found one where the transmission switch was suggested to be the culprit, but having no DTCs present and NO MIL to go get a good start has got my head spinning.
So, If anybody can give me an idea were to beging dissecting the problems or suggest a better scanner to look deeper into the brain of the CPU I'd welcome suggestions, I heard that Autel MaxiDiag JP701 Diagnostic Scan Tool is a good option, but after the experience with CEN-TECH I'm not sure, unless someone with firsthand experience can recommend it.
I thank in advance to all of you that can point me in the right direction.

 

[Kodatech]

37 views and no responses, so Ill give it a try.

First off...when you say VAG, are you talking the VAG1550? Cause that thing is a piece of crap, and probably wouldnt read a Nissan, so you were right in trying another scan tool.

Usually when you get an aftermarket scan tool and it reads something along the lines of "manufacturer dtc" or "unsupported dtc"....or something like that, it means the vehicle has stored a DTC that is specific to that manufacturer, and that manufacturer was not required by OBDII law to release that info to 3rd party companies.

If you could get your hands on a Snap-on Genesis or a Modis or something like that, you could probably get a proper code description. My guess is that the stored codes are transmission codes. When you say "busted radiator" what exactly busted, and how did it bust?

I am a master tech, but I am not a Nissan specialist, so I could be wrong, but in my years of diagnosing and repairing vehicles, I have NEVER seen a default or limp mode that would cause a vehicle to lose reverse and/or neutral.

I think you need some transmission work.

 

[Frontier04]

The scanner that I used is the Ross-Tech VCDS Interface software that is made exclusevely for VWs, but I talk to them and they told me it would work on a general OBDII scan basis and your suggestion about using a manufacturer specific codes makes sense, that's why I'm trying to see if I can get my hand on a better fitted scanner for Nissans, but the Genesis or the Modis are out of my range right now, I'm hoping to get something on the 200 dollar range.
As for the radiator, it had a crack running on top next to the cap, noticeable as soon as you turn the engine on, so I bought a new one and replaced it. I forgot to mention that I also replaced the battery, I don't know if that erased any DTCs that were stored, but wouldn't they come back after a while?.
I know the transmission may not be related to the other issues, and I'm aware that it could range from control linkage and PNP swith and wiring (my hopes) to more serious work, like the governor valve and/or torque converter; but I'll deal with that after I get the limp mode fixed. I'll keep posting as I make any progress, I can only work on it in the evenings so advices will make my job easier.
:itsfriday: