# 97 hardbody issues. p1105, p1441



## pwnby (Aug 28, 2017)

Hey everyone, just wanted to ask some advice from those more experienced in hardbody pickups.

Let me start off saying I'm using a bluetooth code reader/diagnostic tool with the torque pro app to get my information. The truck is a 97 with the 2.4L and 134k.

I am getting repeated codes of p0135, p0141, p1105, and p1441. The first two being o2 sensor heater circuits, I have replaced the front o2 sensor and am in the process of replacing the second. I replaced the front o2 sensor, cleared the check engine light, and the code was back for the front sensor on the next start of the truck. I thought before I went through the trouble of replacing the second one, I ran a can of sea-foam through the brake booster line and drove through a tank of gas to see if it cleared up the front o2 sensor code. no luck. I am still getting both o2 sensors on the next startup after clearing the codes.

On to the next two. the P1105 is the map/baro pressure switch solenoid. I have replaced the MAP sensor under the hood with no luck. I checked my wiring, checked all my vacuum lines for cracks or breaks, and the p1105 still comes back up every time. I put the old map sensor back in and tested my wires coming out of the plug with a multi-meter. I got my constant 5v, ground, and the voltage for my feedback line increased as i gave the truck throttle as it is supposed to. This was proof enough to me that the map sensor is functioning correctly and the wiring was OK.

I pulled the bed off the truck today and found another boost sensor behind the gas tank similar to the MAP sensor. The only difference is the barb for the vacuum line comes out at a 90 degree angle instead of straight down like the one under the hood. the numbers on the sensor are PS55-01, G, and 6x28. It does say BOOST SENSOR on the top of it.

Could this other boost sensor be throwing the p1105 code? I talked to a friend of mine who is a mechanic and he was unaware of any other boost sensor/map sensors behind a fuel tank mounted on the frame.

edit: i was able to find the boost sensor behind the fuel tank on nissanparts, the part number is 25085-1S706 for what it's worth.

As far as the P1441 code goes, is there a way to troubleshoot/test the vacuum cut valve bypass valve, or is it possible that this is just a small leak throwing the code? I am lost as to where to look next! From what I have read online, the issue with the o2 sensors still throwing codes could be the computer itself bad causing my issues. Here are pictures of the o2 sensor data from torque:


Upstream o2 sensor data









Downstream o2 sensor data









I am going to replace the back o2 sensor, seeing as how it isn't sending any change of data to the computer.

Thanks for any information or advice given on this issue.


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## smj999smj (Jan 1, 2006)

My first suggestion is to get a copy of the factory service manual for your vehicle if you don't have one, already. It's a wealth of information! Specifically, you need the "EC" (Engine Control) chapter, which you can download from NissanHelp.com:

1997 Nissan Hardbody Truck Service Manual - Loose Sections - Free with Registration - Nissanhelp.com

The boost sensor near the gas tank is probably the pressure sensor for the evaporative emissions systems and it will not trigger the map/baro code you are seeing. 

The FSM has the component test for the vcv/bypass valve and the testing procedure for that code. 

If it were me, I would go back to the O2 sensor heater codes. My reasoning is that it's possible that all of these codes have a common problem and O2 sensor heater circuits are pretty basic. The heater in the sensor gets its power from the ECM and gets grounded by it. You already replaced the sensor, so, is it a circuit problem with those two wires between the sensor and ECM, the ECM or the ECM grounds? Nissan typically has an EGI ground point on the intake manifold; look for a 10MM head bolt with several black wires going to it. You could do a voltage drop test on it, but, personally, I would just remove the bolt and clean everything up with sandpaper or a wire brush and reassemble. Erase the codes and see what happens.. You can also unplug the ECM and locate the ECM ground wires (usually at one side of the harness connector in a line of several black wires) and use a multimeter to check for continuity, excessive resistance or an open circuit. If those are good, do the diagnostic procedure for the front O2 sensor heater circuit code (most of which you have done at the point) and if all passes, I would suspect a faulty ECM. If you fix that problem, you may end up fixing several or all of the other codes that are setting.


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## pwnby (Aug 28, 2017)

After replacing the map sensor, baro pressure switch, both o2 sensors, and the vacuum cut valve bypass valve, checking all the ground connections I could find on the truck, the same four codes are still showing every time. I have acquired a used ECU from the junkyard out of a 96, mine is a 97. I figured for 30 bucks, it's worth it just to try it out anyway. Is the replacement I bought compatible? Can I use the 96 ECU in my 97 pickup?

pics.
97 ECU currently still in my truck










ECU from the 96










Thanks for the help!


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## pwnby (Aug 28, 2017)

Replaced the ECU with the one out of the 96. Drove it a while, cleared the codes, drove it a while longer, and just this morning i started the truck, cleared all the codes, and started the truck 2 or 3 times. After the third cycle, I am now getting a P0180 for the fuel temp sensor and p1165 swirl control valve. Just thought I'd report back my findings on replacing the ECU.


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