Error 43 - APS sensor

[clivvy]

hi guys,

driving home from Halifax today when all of a sudden, car jerks a bit. MILlight on, weird feeling, like it accelerates more than it should. Limped home and checked the codes - 43, accelerator position sensor open circuit or malfunction.

gave it a liberal dousing of contact cleaner, and test drive ok, but now unsure about driving. Any ideas what this could be or do I need a new sensor/pedal?

 

[makeitfit]

it accelerates more than it should.

Ding dong now that's my kind of error message :sly Tell me how you did it please :naughty

 

[clivvy]

Ding dong now that's my kind of error message :sly Tell me how you did it please :naughty

ha! I know, how weird is that? I was expecting it to cut back, go slow, but just pressing the pedal lightly made it take off! Did get a bit of kangarooing and it seemed to limit acceleration at a certain point....

 

[rayf3262]

ha! I know, how weird is that? I was expecting it to cut back, go slow, but just pressing the pedal lightly made it take off! Did get a bit of kangarooing and it seemed to limit acceleration at a certain point....

That makes sense, as the error code 43 is triggered when the ECU sees an "abnormally high voltage" from the TPS. So you were probably going from 0 -> ~5V in a snap! Hence the sudden acceleration.
Could easily happen if the ground connection to the TPS potentiometer came loose or indeed, if said pot is going flakey..

 

[clivvy]

cheers Ray. All the connections look "as new", so I am not too sure what went wrong. I did tow my mazda early on that morning, otherwise car has been spot on. Anyway, I might source a new pedal assembly or a refurbed one....

 

[clivvy]

oH FFS!!!

this issue has reared its head again today. been totally fine all week, then as soon as I need to go somewhere, code 43 pops up and the car starts acting all weird.

SO, got it back home, and cleaned as best I could the microswitch and connector to it from behind the pedal. Sprayed the linkages etc, and cleared the codes. Took for a drive up the track and it came back.

I am now without any car!!

if these are drive by wire, where does the other end of the wire come out, perhaps I need to check that end?

is it worth me removing the whole pedal for a look??

 

[rayf3262]

oH FFS!!!

this issue has reared its head again today. been totally fine all week, then as soon as I need to go somewhere, code 43 pops up and the car starts acting all weird.

SO, got it back home, and cleaned as best I could the microswitch and connector to it from behind the pedal. Sprayed the linkages etc, and cleared the codes. Took for a drive up the track and it came back.

I am now without any car!!

if these are drive by wire, where does the other end of the wire come out, perhaps I need to check that end?

is it worth me removing the whole pedal for a look??

Without looking at the manual, I seem to recall the wiring goes directly to the ECU, the only connector is the one at the pedal assy.
PITA I know,.. but the best way to check it is with a DVM AT the ECU, the procedure is in the manual.
* Ideally check it with ECUtalk.. grab an interface for ~ 15 quid, the s/w is free....*

 

[briggie]

How much ?????

http://www.ebay.co.uk/itm/1999-NISS...arts_Vehicles_CarParts_SM&hash=item4aadf32b75

 

[rayf3262]

http://www.ebay.co.uk/itm/1999-NISS...arts_Vehicles_CarParts_SM&hash=item4aadf32b75

Yea I know,.. I think someone quoted Nissan dealer price of ~400 quid!
So 175 could be viewed as a bargain!!

 

[clivvy]

Yea I know,.. I think someone quoted Nissan dealer price of ~400 quid!
So 175 could be viewed as a bargain!!

nope, no bargain, its the wrong pedal!

I have to drive it tonight to drop my other half off a few miles up the road, hopefully it will get me there and back. then, tomorrow morning, I am going to take the whole pedal out (safe to do?) and take a good look at the throttle and microswitch, and give them both a proper clean....fingers crossed that does the trick.

 

[briggie]

nope, no bargain, its the wrong pedal!

I have to drive it tonight to drop my other half off a few miles up the road, hopefully it will get me there and back. then, tomorrow morning, I am going to take the whole pedal out (safe to do?) and take a good look at the throttle and microswitch, and give them both a proper clean....fingers crossed that does the trick.

if you need lift mate , ring me :thumb2

 

[clivvy]

update on this:

problem still exists on and off, after removing pedal assembly and giving everything a clean. I couldnt get the microswitch apart, but noted some very small movment in one of the wire connector, not sure how relevent that is. My problem now is that when the MIL light comes on, I can use a feather on the pedal and off it goes, revs staright up to 2k rpm, then when you try to drive properly, it looses power under load, such as drivig up hill.

If the MIL goes out, everything returns to normal.

anything I can do, or do I need a new pedal or microswitch?

 

[rayf3262]

update on this:

problem still exists on and off, after removing pedal assembly and giving everything a clean. I couldnt get the microswitch apart, but noted some very small movment in one of the wire connector, not sure how relevent that is. My problem now is that when the MIL light comes on, I can use a feather on the pedal and off it goes, revs staright up to 2k rpm, then when you try to drive properly, it looses power under load, such as drivig up hill.

If the MIL goes out, everything returns to normal.

anything I can do, or do I need a new pedal or microswitch?

The voltage from the TPS with pedal at rest should be ~ less than 1 volt, if it significantly higher than 1 volt as soon as the pedal is pressed the idle switch opens and the ecu will see the voltage from the TPS as the desired throttle position. This will result in the engine revving to a speed commensurate with the TPS voltage, not good!

Have you actually measured the TPS voltage? You will probably find (during faulty conditions) that is is way too high.
The way the TPS is wired, your symptoms would suggest that the ground is intermittent, this could of course be happening inside the TPS unit.

I suggest you semi-permanently connect a meter to the TPS signal and monitor it, you will most likely see it jump upward randomly.

 

[clivvy]

cheers Ray, I have no idea how to do this! I dont know how to connect the meter, or where. I havent measured the voltage yet however, just because I dont know where to connect. Am I right in thinking the ground wires are the two small wires in the engine bay?

I may be getting a new pedal, just waiting for a chap to get back to me with a picture and price, but it would be handy to test my current pedal and maybe even fix it. Can you advise me where to connect my meter?

 

[rayf3262]

cheers Ray, I have no idea how to do this! I dont know how to connect the meter, or where. I havent measured the voltage yet however, just because I dont know where to connect. Am I right in thinking the ground wires are the two small wires in the engine bay?

I may be getting a new pedal, just waiting for a chap to get back to me with a picture and price, but it would be handy to test my current pedal and maybe even fix it. Can you advise me where to connect my meter?

Ok..
The Throttle unit connector is shown in the top R/H corner of the diagram:
Pin 5 should be a constant 5 volts.
Pin 4 should be at ground.
Pin 2 is the TPS output - this should swing from about a volt or less up to around 5 volts with the pedal fully depressed.
Pin 1 & Pin3 are the IDLE switch.


Connect the -ve meter lead to an earth point inside the vehicle.
with the meter set to ohms (200) connect the +ve lead to Pin 4, check the meter for a near zero value to confirm the ground connection.

Set the meter to DC volts (20)
With the -ve meter lead still connected to the earth point, now connect the +ve meter lead to Pin 5 an and check for ~ 5 volts.

Next with the meter still on DC volts connect the +ve meter lead to Pin 2 check the voltage moves between ~1 volt - ~5 volts at the pedal is moved across its range from rest to full.

You can also check the idle switch (with the meter set to ohms) by connecting the meter leads across Pin 1 & Pin 3, it does not matter which way round the leads are connected. The meter should read around zero when the pedal is at rest and change to infinity when the pedal is slightly depressed from the rest position. (However, by all accounts yours is working as it should)

All this can be done with the ignition ON but the engine not started.

 

[clivvy]

awesome Ray, thank you so much!! great guide, even I can follow that!! I will do this tomorrow night when I get home from work, looks like i'm getting a lift into work...

 

[clivvy]

HELPS!

I got a pedal from a breaker, but I still have the same issue!!

I fitted it tonight, and went for a drive. All was well for about 2 to 3 miles, then the MIL came on and thump, not much power. Slightly different issues in that there is just a lack of power, as opposed to my old pedal whihc just revved its tits off.

same MiL code anyway, 43, what do I check next>??

 

[Timbo_1975]

What happens if you cycle the ignition? Does that restore it? Is the Limp mode triggerable at will under certain conditions ?

 

[clivvy]

Timbo, once the MiL is on, it seems to stay on untill I turn off. Sometimes it will re appear and problem be present upon ignition, othertimes its ok for so long then comes on. So, its kinda random!

I have just been out and followed Rays guide as bext I can, although my pedal is the two connector, not the single connector I think his diagram refers to. I tried to match up the wires as best I understand it, and I do get ground, but I get nothing on pin 5 or 4 or 2!! But, that could be me doing it wrong....as I say, mines is two connectors, not one, so there are six wires, not 5...!!



**oh, as for triggering it, it seems random tbh. With this new pedal, it was after about 5 - 10 mins...

 

[clivvy]

can anyone advice me on the next step? I would really liek to confirm voltage at the pins, but I am getting nothing, but although I got ohms at the ground pin, I wonder if I am doing it right, because I get nothing at all when I use volts on the meter!!

should I be checking the ECU next, because the wires form the pedal just go there, and no where else? Also, where is my ecu, its a 1997 Maverick, not sure where to look or what it looks like!