Accelerator Pedal - Code 43 HELP!

[clivvy]

ok chaps, decided to start a new thread as I have a Consult plus some videos of my issues

This is the problem:

MiL light on, error code 43 - Accelerator position Sensor
Symptom - random power, foot down either makes it go, or does nothing.


video here shows me using ECU talk. I am pressing the pedal on and off, you can see the erratic idle, and you can see the voltage is not consistent.

This is using a pedal I bought from a breaker, but the issue is the same on my old pedal, so now I need to know what to check next...!!

 

[Timbo_1975]

Right.

Obviously your idle switch is dicking around, by the looks watching the video. When the idle switch is closed, the ecu will not allow the engine to rev. It should open the moment you press the pedal. If you have changed the pedal assembly, is there a problem with the multiplug, or damage to the cable on up? I know the wires are very fine!


Doesnt look to be any problem with the potentiometer output, although I would like to see over 4v with the pedal on the floor. Can you confirm ?

Also *carefully* check the brake pedal microswitch, as if this is playing up, again you'll only get engine idle. Make sure the pedal fully returns against the stop and the spring isnt bust. You should be able to see this operating in ecutalk.

 

[clivvy]

Right.

Obviously your idle switch is dicking around, by the looks watching the video. When the idle switch is closed, the ecu will not allow the engine to rev. It should open the moment you press the pedal. If you have changed the pedal assembly, is there a problem with the multiplug, or damage to the cable on up? I know the wires are very fine!


Doesnt look to be any problem with the potentiometer output, although I would like to see over 4v with the pedal on the floor. Can you confirm ?

Also *carefully* check the brake pedal microswitch, as if this is playing up, again you'll only get engine idle. Make sure the pedal fully returns against the stop and the spring isnt bust. You should be able to see this operating in ecutalk.

Cheers Timbo. The two plugs at the top of the pedal appear good, wires sound and no dirty grease or grime. The smaller microsswitch plug again, looks ok. I tried to follow the wires into the loom, and all looks fine.
As for seeing 4V, I was flooring the pedal most of the time in the videos, basically id press a few times to rev, floor it, then let the pedal go...

I havent checked the brakes, so thats a good point I will check that later today. It does feel ok, but I have never inspected closely.

 

[clivvy]

anything else I should check? do the results I show mean a short in the wiring, or still a faulty pedal?

 

[clivvy]

I checked the brake pedal, this appears ok. I can see the connector, I unplugged it and inspected, seems ok, and the two wires coming from it appear in tact.

Shoudl I be finding my ECU next to check if it is that at fault???

help!! I am starting to get worried now about the car as its undriveable....!!!

I iwll hook it back up to the laptop tonight, and take some pics of the brakes if relevent, and i think I may start trying to find the ecu.

 

[Timbo_1975]

Can you confirm that the Idle switch switches on and off on the screen as you touch the pedal and then release. It must do this every time.

Also the Brake pedal switch. You should be able to see this in consult also, if you enable the right gauge.

I'd then want to verify the 5v feed at the pedal with it connected incase something is pulling it down.

Whilst you're there, check the ground. Should be within 0.2v of 0.

If the ECU doesnt get back a 0 - ~ 4.5v signal because of either the above its never going to work properly.

 

[clivvy]

ok, I got these results:



now, I couldnt find a gauge for the brakes, or at least not one that said "brakes" in it!! not even close. Developments on this fault are now it wont actually rev, as you can see in the video....im not happy...

what next?!

oh, just a thought, yesterday I unplugged the brake switch (from top of pedal) and plugged back in. I didnt start the car, nor was the ignition on when I did it, and now it wont rev....

oh yeah, as for ground, I checked that with the multimeter a few days ago and I got around 0.9v I think it was....

 

[Fez_uk]

might not have breaks sensor as the maverick has no ABS?

 

[clivvy]

could well be Fez....

 

[Fez_uk]

as it won't rev after messing with the brake pedal maybe something in that is faulty?

 

[clivvy]

does seem a coincedence, but its hard to see what? wires looked in tact, although I noted black shrinking or tape around two sections of the wire.....think I will try take a pic.

 

[rayf3262]

does seem a coincedence, but its hard to see what? wires looked in tact, although I noted black shrinking or tape around two sections of the wire.....think I will try take a pic.

As per Timbo's advice, you need to check the operation of brake switch (circled in red) for correct operation.
Start with page EC-205 onward....

These things suffer a lot of mechanical stress, and can be prone to faulty/intermittent operation, which can easily give rise to oddities.
I'll also add, that it is unlikely that the ECM/ECU is at fault, it is very probably going to be a bad connector/partially fractured wire/misbehaving switch/dodgy ground connection etc...
Pain as it is, you will need to get down and dirty with a meter and check the connections from source to the ECU.

 

[clivvy]

jeepers....I have no idea what I am looking at!

ok, so, I will get my multi meter, unplug the brake switch and test the pins...? see what voltage I get? I dont mind getting down and dirty, see here from tonight:

ECU found

finding ECU

brake switch?

my problem is I dont know electricals!

 

[clivvy]

oh hold on, I think I can read the schematic now. Follow that line to the ECM, so presumably I find the corresponding wire or number on the ecm and test that too? Glad I pulled it out now! I will do this tomorrow night. So, test at the switch end, then at the ecm end, do I need ignition when testing, or off? I presume off...

incidentally, for a giggle, I started the car up, and now it revs.....

 

[rayf3262]

incidentally, for a giggle, I started the car up, and now it revs.....

That kinda proves that you have a loose connection or similar somewhere....

You test with ign. on and check for appropriate voltage changes ALSO check (as per the manual test procedures) for correct continuity point to point.
Don't forget to wiggle connectors & wiring while checking, as you could easily read good then something moves and .....
Probably even a good idea to check it with the engine running as the vibration at tick over may induce the fault?

 

[clivvy]

That kinda proves that you have a loose connection or similar somewhere....

You test with ign. on and check for appropriate voltage changes ALSO check (as per the manual test procedures) for correct continuity point to point.
Don't forget to wiggle connectors & wiring while checking, as you could easily read good then something moves and .....
Probably even a good idea to check it with the engine running as the vibration at tick over may induce the fault?

ok Ray, thanks very much I will try this tomorrow. I did try to give all the loom I could see a good wiggle. I was going to reattach the laptop, but I live on a quiet cul-de-sac and I dont want to make a nusiance revving the tits off my car. Although I found it difficult to trace the brake wires and the accelerator wiring, I will have another look tomorrow night. I get the distinct impression that much of this dash has been our before, there is also bits of electrical tape here andthere that are clearly not Nissan related....

 

[Timbo_1975]

I'd add that the BP switch is a normally closed flavour, it opens on pressing the brake, so any break in the cable or a non-connected plug, will cause a no-rev. i.e. it fails safe.

0.9v on the ground connection is too high also.

 

[clivvy]

I'd add that the BP switch is a normally closed flavour, it opens on pressing the brake, so any break in the cable or a non-connected plug, will cause a no-rev. i.e. it fails safe.

0.9v on the ground connection is too high also.

dammit.

ok, I will re check the ground using my multimeter tonight, and i will re check the brake connection. I have removed most of the centre console now so I can see the wires. How safe is it to unplug from the ECU to give the connectors an inspection? should I unplug the battery?

 

[Timbo_1975]

Check the ground connection back to the battery -ve. You'll need one long test lead and you should do this with the ignition on i.e. with the system under load. Often a poorly earthed ECU is the culprit...

To disconnect the ecu's multiplug, I would disconnect the battery first. Just to be safe. Ensure the ignition is OFF. Then bell through the wires from one end to other.

I tend to use a test lamp of 5w as you want to load the wire. Often a fault will still show voltage but its unable to pass any current.

 

[clivvy]

Check the ground connection back to the battery -ve. You'll need one long test lead and you should do this with the ignition on i.e. with the system under load. Often a poorly earthed ECU is the culprit...

To disconnect the ecu's multiplug, I would disconnect the battery first. Just to be safe. Ensure the ignition is OFF. Then bell through the wires from one end to other.

I tend to use a test lamp of 5w as you want to load the wire. Often a fault will still show voltage but its unable to pass any current.

cheers Timbo, I will give it a shot, but I dont have any etsting leads or lamps etc, just a multi meter! The ECU ground...I dont recall seeing one, do you know where on the ECU it would be? I may not have looked properly, but all I can see are the wires going in with a plastic protective cover over them....!

I will check all ground conenctions again, but I replace the big one from the battery a few years ago due to corrosion, am I right in thinknig the two very small ground wires attached to the top of the engine block, drivers side, go back to the pedals?