Throttle body & pedal sensor problems.

[Arsenal01]

Hi all,
I own a 2004 Skyline V35 300 GT. The engine light came on recently, took it to the mechanics and the ECU said the throttle body & pedal sensor were having problems. Got them both replaced (2nd hand parts), problem persisted and unfortunately mechanic wasn't sure how to resolve this so recommended me to a more experienced mechanic. Took it to mechanic B, they inspected all the wiring and electricals and found nothing faulty. They couldn't figure out what's wrong, except suggest possibly replacing those parts with brand new ones however unfortunately to get them brand new will cost upwards of $1,600 and possibly 2-3 month delivery from Japan. That isn't really an option I'm willing to take since it's not even a guarantee that would fix it. After doing research online, I've seen that the ECU needs to relearn the throttle body and idle. I've attempted to do the tests MANY times, multiple variations, however I am not having luck in succeeding. It says that all electricals must be unplugged for it to work, however my car comes with the GPS DVD thingy which draws power when turning the power on (not engine). Is there something that I could be missing in regards to reset the ECU and have it relearn the peddle/throttle?

Essentially the car just struggles to get power, sometimes changes gears correctly or changes them at approximately 5-6k+ revs, or suddenly draws a lot of power out of nowhere. 

[V35_Paul]

Do you have Cruise control?

I had the similar problem and had a blow fuse in my "aftermarket" cruise control.

[Arsenal01]

On 1/5/2022 at 12:11 PM, V35_Paul said:

Do you have Cruise control?

I had the similar problem and had a blow fuse in my "aftermarket" cruise control.

Unfortunately it does not have a cruise control feature. I'm at my wits end trying to figure out what else it could possibly be.

[V35_Paul]

 

Did you use these to do the reset?

[Arsenal01]

On 1/12/2022 at 3:19 PM, V35_Paul said:

 

Did you use these to do the reset?

For the life of me, I've attempted every single procedure I've found online, in every variation multiple times but have had no luck. Yesterday I disconnected the negative terminal from my battery, pumped the brakes and left it over night as advised by other which can reset the ECU. Hopefully when I get home from work today, the ECU reset is successful.

[V35_Paul]

On 1/12/2022 at 1:16 PM, Arsenal01 said:

For the life of me, I've attempted every single procedure I've found online, in every variation multiple times but have had no luck. Yesterday I disconnected the negative terminal from my battery, pumped the brakes and left it over night as advised by other which can reset the ECU. Hopefully when I get home from work today, the ECU reset is successful.

Yeah that's for older Skylines like the R33.

When your doing the throttle reset can you hear it moving? Or get someone to listen for it. 

Or when your doing the ECU reset does the CEL turn off at all?

If you can hear it resetting then it's properly working. If the CEL goes out then it's working.

But if your problems aren't going away these aren't your solutions. 

What are the codes that are coming up?

[Arsenal01]

On 1/12/2022 at 7:02 PM, V35_Paul said:

Yeah that's for older Skylines like the R33.

When your doing the throttle reset can you hear it moving? Or get someone to listen for it. 

Or when your doing the ECU reset does the CEL turn off at all?

If you can hear it resetting then it's properly working. If the CEL goes out then it's working.

But if your problems aren't going away these aren't your solutions. 

What are the codes that are coming up?

I've tried many times doing the procedure you showed and other variations for the ECU reset and throttle body relearn procedure. However, not once have I got the engine light (my car just has the old school engine light in yellow, no writing with it) to flicker when doing the ECU reset or have the throttle body make a sound when doing the relearn procedure. Sometimes when I turn my car on, the engine light isn't on. Car drives fine for about a second or 2 then it goes into limp mode and the check engine light comes on 100% of the time. When I leave it in park and rev it (before engine light comes on without driving), I can hear a clicking sound around 2.5k-3k revs happen a few times, the revs drop down when it happens. Rev the engine again then boom, limp mode and engine light comes on. Unfortunately I didn't get the codes from the mechanics when I took it in, however I'll call up and see if they possibly remember. I just remember them saying the ECU codes say it was the throttle body and pedal sensor.

Ive tried probably 20-30 times however haven't succeeded once in either ECU reset or throttle body relearn procedures and I've tried it with a stopwatch within milliseconds of error.

[Arsenal01]

On 1/12/2022 at 7:02 PM, V35_Paul said:

Yeah that's for older Skylines like the R33.

When your doing the throttle reset can you hear it moving? Or get someone to listen for it. 

Or when your doing the ECU reset does the CEL turn off at all?

If you can hear it resetting then it's properly working. If the CEL goes out then it's working.

But if your problems aren't going away these aren't your solutions. 

What are the codes that are coming up?

So I recently bought an ODB-II code reader, plugged it in and seen the fault code coming up is P0121. I can clear it through the reader app, but yeah it just constantly comes back up.

[V35_Paul]

Looks like you might have got a dodgy 2nd hand throttle body. You can do some testing on it. If you got multi meter skills and find out what the values are meant to be coming though the sensor.

Or if you know anyone with the same car do a swap with TBs and see if the problem goes away. Then you can spend the money for a new one.

Also you will get your money back for the faulty one you bought. If it came from a wrecker.

[Arsenal01]

On 1/13/2022 at 5:47 PM, V35_Paul said:

Looks like you might have got a dodgy 2nd hand throttle body. You can do some testing on it. If you got multi meter skills and find out what the values are meant to be coming though the sensor.

Or if you know anyone with the same car do a swap with TBs and see if the problem goes away. Then you can spend the money for a new one.

Also you will get your money back for the faulty one you bought. If it came from a wrecker.

 

I followed the test on that for my original throttle body, and noticed I wasn't getting any readings when doing the tests connecting Red to D - Black to E and also Red to A - Black to B. I will do this test tomorrow or over the weekend when I have time with the 2nd hand replacement I got and see if I get a reading my the MM or not.

Athough they're not the exact same type of TB, I'm assuming that they should atleast show some sort of reading as well. The initial test of Red to C and Black to E showed 1.45 which is within the suggested parameter.