# Engine runs but wont rev up.



## sunway (Apr 11, 2017)

Hi all,
I have a 2005 Nissan X-Trail 2.0L QR20.
This morning it started, but when the accelerator is pressed, the engine won't rev. It will move slowly on idle power if you put it in gear. The engine light came on. I tried using the pedal trick to get the code but couldn't. I ordered a scan tool online, but while waiting for it, I thought I would research possible causes. Yesterday it seemed like the gas pedal had a delayed response.

I was thinking of the following:

Throttle position sensor.
Accelerator position sensor.

Any advice would be greatly appreciated.


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## otomodo (May 23, 2008)

I would say you re on the right track. 

HO MALA?
Acarta pà grota


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## tonyvancity (Jan 2, 2017)

...possibly symptoms of the cam sensors? search for that thread on here, i think in the past various owners were discussing a lack of power or engine in xtrails not turning over due to bad cam sensors. HERE is the thread if it helps a bit...http://www.nissanforums.com/x-trail/158372-engine-stall-fuel-pump-crank-sensor.html (two sensors to replace....i have not replaced mine yet...but others mentioned it is cheaper to buy a cam sensor kit from the nissan parts dept rather them the aftermarket....if that is what your issue is.)


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## MikeHJ (Mar 7, 2017)

Sounds like you're in limp mode, which can be triggered by a lot of things: various sensors, electrical issues, computer issues, etc. Good news is that a lot of these things can simply be reset, others are pretty simple to fix.

Pull the codes first, otherwise it's bit of wild goose chase.


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## quadraria10 (Jul 6, 2010)

Hard to say if its sensor related, but if you are patient , use a watch for timing, and keep trying the manual method does work. When it starts repeatedly flashing the code you will need to count and note the long and short dashes. You will then be able to get and even clear the fault code(s). I am assuming you found the instructions on how to do this. When you figure it out just google it and you will be on track to figure out what is wrong. Sounds like you are in safe mode. Hopefully its nothing too serious or expensive but you will need to get the faut code to put you on the path of knowing what needs fixing. Good luck.


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## sunway (Apr 11, 2017)

Thanks for all the advice. I was able to pull the codes today:

P2122 Throttle/Pedal Position Sensor? Switch D circuit Low

P2127 Throttle/Pedal Position Sensor? Switch E circuit Low

That would explain why I couldnt get the codes manually.

The shop manual says not to remove sensor but I guess at this point I have nothing to lose? I just hope I can do the relearn.


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## quadraria10 (Jul 6, 2010)

Try cleaning the contacts for the connections. Good luck with it.


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## rogoman (Dec 16, 2004)

sunway said:


> Thanks for all the advice. I was able to pull the codes today:
> 
> P2122 Throttle/Pedal Position Sensor? Switch D circuit Low
> 
> ...


Here's a quick run-down of how the sensors work as taken from the FSM for your vehicle:

The accelerator pedal position sensor is installed on the upper end
of the accelerator pedal assembly. The sensor detects the accelera-
tor position and sends a signal to the ECM.
Accelerator pedal position sensor has two sensors. These sensors
are a kind of potentiometers which transform the accelerator pedal
position into output voltage, and emit the voltage signal to the ECM.
In addition, these sensors detect the opening and closing speed of
the accelerator pedal and feed the voltage signals to the ECM. The
ECM judges the current opening angle of the accelerator pedal from
these signals and controls the throttle control motor based on these
signals.

Idle position of the accelerator pedal is determined by the ECM
receiving the signal from the accelerator pedal position sensor. The ECM uses this signal for the engine oper-
ation such as fuel cut.

When the malfunction is detected, the ECM enters fail-safe mode and the MIL lights up.

--------------------------------------------------------------------------------------------------------------------------

Here are the possible causes of the malfunction:

For a P2122:
- Harness or connectors (The sensor 1 circuit is open or shorted.)
- Sensor 1 is defective.
- Bad ground connection.
For a P2127:
- Harness or connectors (The sensor 2 circuit is open or shorted.)
- Sensor 2 is defective.
- Bad ground connection.

If you replace the accelerator pedal assembly, then you'll have to perform the following procedures:
"Accelerator Pedal Released Position Learning" .
"Throttle Valve Closed Position Learning" .
"Idle Air Volume Learning" .

These procedures are explained in the FSM. You can get a copy of the FSM from this web site:

https://ownersmanuals2.com/get/niss...nual-emission-control-system-section-ec-38671


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## sunway (Apr 11, 2017)

Well I replaced the pedal sensor without any resulting changes. So I guess now I have to check the ground connection or the connection to the ECU. I am right the connections from the pedal go to the ECU? What would be the best way to go about doing this? Can I check with a voltmeter at the connection to the ECU?
Thanks


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## sunway (Apr 11, 2017)

I feel like an idiot. I cannot even find these grounds. I cannot post a picture that I am going by in the manual. What is the steering member? it looks like it goes horizontal across the front?


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## quadraria10 (Jul 6, 2010)

Not sure why don't you post the section and page from the service manual. As for the ground points they are illustrated in the service manual PG section. I just provided a link to it in the thread about the cigarette lighter and radio not working. Did you perform the relearn procedures Rogoman specified?


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## rogoman (Dec 16, 2004)

sunway said:


> Well I replaced the pedal sensor without any resulting changes. So I guess now I have to check the ground connection or the connection to the ECU. I am right the connections from the pedal go to the ECU? What would be the best way to go about doing this? Can I check with a voltmeter at the connection to the ECU?
> Thanks


The connections from the pedal sensors do go to the ECM. Since you have a copy of the FSM, the voltages and measuring points are explained in the FSM.



sunway said:


> I feel like an idiot. I cannot even find these grounds. I cannot post a picture that I am going by in the manual. What is the steering member? it looks like it goes horizontal across the front?


The steering member is the housing that runs from the steering wheel down through the firewall. To locate all the ground connections, try laying on your back and slide yourself way up against the firewall; not the easiest thing to do unless you're a contortionist. Worst case, you may have to remove the instrument panel.


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## sunway (Apr 11, 2017)

Thanks! I have been busy with work so left it for a bit. Fortunately I can walk to work. Anyways I read the service manual and made myself some notes highlighting what I don't know. Oddly my power door locks are not working now...maybe I knocked a harness off? Anyways if anyone can ritique my thinking below will be greatly appreciated.

I did the relearn procedure without success which would make sense if the wiring is broken.

According to EC-413 the first diagnostic procedure is to check the ground connections following the instructions in EC-132.
EC-413 also shows three diagrams locating the relevant grounds of:

M27, M70 and F49.
Also in section PG:
PG-16 shows M27
PG-18 shows M70
PG-24 shows F49

I see now where the locations of M70 and M27 are and started to remove some panels. It looks like I have to remove* the instrument panel. I started to remove it and it detached at the back but the front part won’t budge.*
As for *F49 called body ground in EC-413 and engine ground in PG-24 I cannot see it where I think it should be ... the left side kick panel?*

Step 2 is: CHECK APP SENSOR 1 POWER SUPPLY CIRCUIT
Check voltage between APP sensor terminal 6 and ground with tester. This I can do just need to find my voltmeter….it should be 5V….if it is go to step 3 otherwise repair circuit.
Step 3: CHECK APP SENSOR 1 GROUND CIRCUIT FOR OPEN AND SHORT
Check harness continuity between APP sensor terminal 3 and ECM terminal 82.
Refer to Wiring Diagram…. I can do this.
*Also check harness for short to ground and short to power. Not sure how to do this?*

4. CHECK APP SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
Check harness continuity between APP sensor terminal 5 and ECM terminal 106.
Refer to Wiring Diagram….I can do this.
Also check harness for short to ground and short to power….not sure again.

So basically I am checking the wires from the sensor harness to the ecm are continuous.
The last step would be to check would be to connect the harness and with ignition on *(engine on?)* check that I get the varying voltages depending on the pedal position according to EC-417, EC-418.
For example it says: 
1. Reconnect all harness connectors disconnected.
2. Turn ignition switch ON.
3. Check voltage between ECM terminals 106 (APP sensor 1 signal), 98 (APP sensor 2 signal) and ground under the following conditions.

I am a little confused here. I put one lead on the body ground and the other on the ecm terminal, but how if all harnesses are connected?


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## rogoman (Dec 16, 2004)

sunway said:


> Thanks! I have been busy with work so left it for a bit. Fortunately I can walk to work. Anyways I read the service manual and made myself some notes highlighting what I don't know. Oddly my power door locks are not working now...maybe I knocked a harness off? Anyways if anyone can ritique my thinking below will be greatly appreciated.
> 
> I did the relearn procedure without success which would make sense if the wiring is broken.
> 
> ...


Ground connector F49 is located behind the passenger's side kick panel (right side). It's near the ECM.

In Step #3 "Also check harness for short to ground and short to power". Make sure ignition is off. Disconnect ECM harness connector. Now with the test meter probes touching the APP sensor terminal 3 and ground, there should be no continuity or any voltage. You can test all 6 APP terminals the same way.

When a procedure calls for testing certain pins on a harness connector while each end is plugged together, you will have to use something called a "back-probe". Something like a paper clip attached to an alligator clip on the probe. Read section GI-23 of the FSM.


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## sunway (Apr 11, 2017)

This is what I did.

I skipped step 1, checking the grounds.

Step 2. With ignition ON checked APP6 to ground on car and got 5V which is what it should be.

Step 3 With ignition OFF checked all APP to ground on car.

APP1 and APP3 both show continuity to GROUND. None showed any voltage.

As a side note the car wont even start now. It turns over but its like an immobilizer/alarm has kicked in...and I smell a little gas. I have another key without a chip which never could start the car but its like when I try with that key.

I wasn't able to check continuity from APP to ECM because the ECM terminals look nothing like the manual. I am pretty sure I have the ECM. Its got a lever. Using the manual I have also identified the ABS module and transmission module so I am pretty I got the ECM. 
The ECM in the manual has a large left part and small right side part whereas mine in the car has two equal parts.


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## sunway (Apr 11, 2017)

Just to follow up and say thanks to everyone that tried to help. I ended uo taking it in to Nissan. They said it was an accelerator pedal stopper what ever that is? that part was 5 dollars. With the tests and everything it was about 140 dollars to fix. They also replaced the airbag sensors they said were on recall. The bad news is during their test drive they noticed a vibration in the engine and recommended an overhaul. They didn't hard sell it but I will seek your advice shortly in a new thread. Thanks again.


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## quadraria10 (Jul 6, 2010)

Thanks for sharing that. It will probably help someone else someday. Engine overhaul? Out of curiosity when was the last time your spark plugs were changed?


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