# 2005 X Trail P2135 Code



## Stringer Bell (Jul 1, 2021)

Last Friday my check engine light came on. I had been doing a lot of driving the past 3 days and it was a very warm day on Friday. My car would not accelerate after the check engine light came on. I ran a diagnostic and the code indicated that the Throttle/Pedal Sensor Switch A/B Correlation. It has not happened since. 

I have done some reading as per link

Is there any cause for concern? should I replace any of the senors as a precaution?


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## rogoman (Dec 16, 2004)

Stringer Bell said:


> Last Friday my check engine light came on. I had been doing a lot of driving the past 3 days and it was a very warm day on Friday. My car would not accelerate after the check engine light came on. I ran a diagnostic and the code indicated that the Throttle/Pedal Sensor Switch A/B Correlation. It has not happened since.
> 
> I have done some reading as per link
> 
> Is there any cause for concern? should I replace any of the senors as a precaution?


There is a concern. If it happens again, the engine will operate in "fail safe" mode which will limit the RPMs. At this point, download a copy of the FSM for your vehicle; section EC.PDF is the one you need to read; it provides ground points to inspect and excellent diagnostic procedures for trouble shooting:





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2005 Nissan X-Trail PDF Owner's Manuals






ownersmanuals2.com





Inspect the harness connectors on the throttle body for looseness but don't unplug any of them; also if you plan to replace the throttle position sensor on the throttle body. If you do, you'll have to perform the "idle air learning procedure". It's a very detailed and tricky process. Otherwise the idle will become unstable.


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## Stringer Bell (Jul 1, 2021)

rogoman said:


> There is a concern. If it happens again, the engine will operate in "fail safe" mode which will limit the RPMs. At this point, download a copy of the FSM for your vehicle; section EC.PDF is the one you need to read; it provides ground points to inspect and excellent diagnostic procedures for trouble shooting:
> 
> 
> 
> ...


Thank you so much for the reply. The info you provided has helped me a lot. There is diagram that is referenced when troubleshooting the APP and throttle position sensor. It is located on page 838 in reference to the TP sesnsor. It is again referenced on 1628 for the APP. Is this a generic diagram? If not, I can not seem to find it on the vehicle.


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## VStar650CL (Nov 12, 2020)

Stringer Bell said:


> There is diagram that is referenced when troubleshooting the APP and throttle position sensor. It is located on page 838 in reference to the TP sesnsor. It is again referenced on 1628 for the APP. Is this a generic diagram? If not, I can not seem to find it on the vehicle.


If the Exxie manual follows the normal Nissan form (I have no way to be sure, we have no Exxie documentation here in the 'States), the APP and TPS will both be in the EC manual section, with a DTC-specific wiring diagram accompanying the troubleshooting text for each DTC. The global engine control wiring diagram will be called "Non-DTC" and will be somewhere near the end of the EC section.

"Glitchy" APP and TPS codes that come and go tend to caused by wiring or pin-fit problems. In particular, the TPS wires often make an unsupported loop between the harness body and the throttle body connector, which can fatigue with years of vibration. The good news is, if it is a wiring problem, both the TPS and APP wires always run directly from sensor to ECM with no intervening connectors. This makes it easy to fix by simply routing new parallel wires between the two.


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## Stringer Bell (Jul 1, 2021)

I tried to follow the DTC Confirmation procedure outlined in the relevant sections, without a Consult -II. It did not work. From what I read, "it is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit has a malfunction". Might narrow down my problem but will go through everything. Its good to know about the wiring solution, in case I need to use it . Will have to use a multi meter to get some readings..


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## rogoman (Dec 16, 2004)

Stringer Bell said:


> Thank you so much for the reply. The info you provided has helped me a lot. There is diagram that is referenced when troubleshooting the APP and throttle position sensor. It is located on page 838 in reference to the TP sesnsor. It is again referenced on 1628 for the APP. Is this a generic diagram? If not, I can not seem to find it on the vehicle.


The two wiring diagrams are not generic. One is for the APP to ECU; the other one is for the TP to ECU. The ECU is looking at all four sensors; thus the two separate wiring diagrams.


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## VStar650CL (Nov 12, 2020)

rogoman said:


> The two wiring diagrams are not generic. One is for the APP to ECU; the other one is for the TP to ECU. The ECU is looking at all four sensors; thus the two separate wiring diagrams.


The reason there are two for each is a failsafe, the older manuals all have graphs to show either voltage or resistance across the range of the pedal and throttle butterfly movement. The APP's usually use potentiometers that operate in the same direction but with a different slope, TPS's usually operate at the same slope but in opposite directions. The principle is the same, the percentage difference between the sensors remains the same regardless of the sensor supply voltage, so the ECM can always diagnose which sensor has failed under any circumstance. So whichever sensor A or B the DTC directs you to, you can be certain it's that exact sensor or those exact wires causing the issue.


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## Stringer Bell (Jul 1, 2021)

I checked the connections and they seem to be snug. Also the wires dont seem to be frayed or stripped. I am finally getting around to checking the voltage of the APP and TPP. Once I unplug it, as rogoman mentioned, I will have to perform the idle air volume learning procedure after I complete my checks.
The only part I can not make sense of is: ignition timing M/T: 15 ± 5° BTDC (in Neutral position) A/T: 15 ± 5° BTDC (in P or N position). How do I view this in my vehicle? I do not have a CONSULT -II.

Also does this procedure involve putting the vehicle in diagnostic mode? There is warning about it before the steps are outlined. If that is the case should I just change the APP, since it is impossible to switch to diagnostic mode if there is a malfunction in the circuit for APP?


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## VStar650CL (Nov 12, 2020)

Stringer Bell said:


> Also does this procedure involve putting the vehicle in diagnostic mode? There is warning about it before the steps are outlined. If that is the case should I just change the APP, since it is impossible to switch to diagnostic mode if there is a malfunction in the circuit for APP?


The ECM will not behave normally with an active APP DTC, so you'll need to get that resolved before checking any tuning factors. If your Exxie is a QR25 with COP ignition, then the ECM is controlling the ignition timing and there's nothing to set. You can "bump" it using work support on a scanner, but that comes with its own set of problems,. Once you tinker with it, you can't perform an IAVL without un-tinkering it first. In all my years with Nissan, I've never needed to touch it on a distributor-less engine.


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## Stringer Bell (Jul 1, 2021)

VStar650CL said:


> *The ECM will not behave normally with an active APP DTC, so you'll need to get that resolved before checking any tuning factors*. If your Exxie is a QR25 with COP ignition, then the ECM is controlling the ignition timing and there's nothing to set. You can "bump" it using work support on a scanner, but that comes with its own set of problems,. Once you tinker with it, you can't perform an IAVL without un-tinkering it first. In all my years with Nissan, I've never needed to touch it on a distributor-less engine.


So should I just replace my APP sensor? There is no active DTC as far as when I plug in my code reader. It just came up once and hasn't come up again as outline in my OP


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## VStar650CL (Nov 12, 2020)

Stringer Bell said:


> So should I just replace my APP sensor? There is no active DTC as far as when I plug in my code reader. It just came up once and hasn't come up again as outline in my OP


No, if it's "past" and it's been erased, you can check anything you please. *BUT* (big but), Nissan APP's almost never fail. I've seen exactly one in about the last decade. Come-and-go APP codes are virtually always wiring or pin-fit problems, not the sensor.


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## Stringer Bell (Jul 1, 2021)

VStar650CL said:


> No, if it's "past" and it's been erased, you can check anything you please. *BUT* (big but), Nissan APP's almost never fail. I've seen exactly one in about the last decade. Come-and-go APP codes are virtually always wiring or pin-fit problems, not the sensor.


ok I will try to use the multi meter to test voltage while the sensors are still connected to avoid the IAVL


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## VStar650CL (Nov 12, 2020)

Didn't realize you were worried about that, please don't. Disconnecting the APP for testing won't require an IAVL or CTPL, that's only needed if you replace it.


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## Stringer Bell (Jul 1, 2021)

I think I need a crash course on how to use a multi meter despite reviewing youtube videos. Step 2 of the diagnostic procedure it says to:" Check voltage between APP sensor terminals 4, 6 and ground
with CONSULT-II or tester." 
I am not even getting a reading. Which is bizarre because its the power supply. I am checking 4 and 6 individually. I even tried to stick a paper clip in and tried different grounds.


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## VStar650CL (Nov 12, 2020)

Safety pins are the best for back-probing. The A and B sides of the APP have completely separate power, ground and signal wires, so check the power supply and ground on the "good" side of the APP to verify your meter. If the meter checks okay and there's no voltage at any of the terminals on the "bad" throw, it means the 5V power wire between the ECM and APP is broken. The APP uses 3-leg potentiometers with one leg connected to 5V, one to ground, and the wiper leg producing an analog voltage. So without 5V power, you'll see 0V at all three terminals.


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## Stringer Bell (Jul 1, 2021)

After disconnecting/reconnecting the APP new fault codes were found. P2127 and P2122


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## VStar650CL (Nov 12, 2020)

You'll get "flatline" codes when the APP is disconnected with the key on for testing. Just erase them.


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## Stringer Bell (Jul 1, 2021)

VStar650CL said:


> You'll get "flatline" codes when the APP is disconnected with the key on for testing. Just erase them.


these codes appeared after I reconnected the sensor and started up the engine.


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## VStar650CL (Nov 12, 2020)

If they're still current then you didn't get the connector seated all the way, those are flatlines (0V) for both the A and B sensors.


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## Stringer Bell (Jul 1, 2021)

UPDATE:

Thanks for the help guys. I ended up taking it in to the mechanic. They said nothing was out of the ordinary but they cleaned and checked the throttle body. Looks like they performed a diagnostic scan while driving and nothing came up. I mentioned to them to check the APP sensor with a meter but I dont think they did, they said everything in their scan turned out normal.

A couple of days later, a new code came up. P0507. From what I read this could be due to a number of issues and one of them could be that the idle air volume learning needs to be performed after cleaning the throttle body. I have tried this a couple of times, to no avail. I will now look for any leaks on the hoses going to the manifold. I will need to get carb cleaner but my initial observation did not turn up anything. I also had trouble finding the Idle Air Control Valve. I thought it was located near the throttle body but I could not see it.

The RPM are at about 700-800 during idle.

Apologies if this issue requires a new thread.


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## rogoman (Dec 16, 2004)

Stringer Bell said:


> UPDATE:
> 
> Thanks for the help guys. I ended up taking it in to the mechanic. They said nothing was out of the ordinary but they cleaned and checked the throttle body. Looks like they performed a diagnostic scan while driving and nothing came up. I mentioned to them to check the APP sensor with a meter but I dont think they did, they said everything in their scan turned out normal.
> 
> ...


The P0507 is coming up because apparently during the cleaning of the throttle body you may have unplugged the harness connector and may have tried to start the engine. In general the main causes of a P0507 are:
● Defective electric throttle control actuator
● Intake system vacuum leak
● PCV system malfunction

Did you actually try performing the "idle air volume learning" procedure? It's very detailed and the timing of the steps have to be precise; best to use a stop watch when doing it.


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## VStar650CL (Nov 12, 2020)

rogoman said:


> The P0507 is coming up because apparently during the cleaning of the throttle body you may have unplugged the harness connector and may have tried to start the engine.


Rogo is right, it may just be a leftover from a lazy tech cycling the key during cleaning and then not clearing it. Now the ECM may be refusing the IAVL because of the DTC, certain DTC's will abort the procedure even if they're "past". Try erasing it and then re-try the IAVL.


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