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VZ LS1 Accelerator Pedal Position Sensor

Fu Manchu

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I should see if I can get a part number off my pedal for you.
 

Jolls

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Hi Fu,
Yes that is exactly what I have. The difference being what your pictures show and what the wiring diagram/B22 diagram reflect. Either the pin numbering for B22 is incorrectly shown (which I think is the case) or the wiring diagram does not match the wiring. If you check your photo against the wiring diagram below and the pinout diagram for B22 you will see what I mean.

The photo of the pedal wiring matches the wiring diagram. 8 pin plug. 6 wires.
These run directly to the TAC Module.
View attachment 216535
View attachment 216536
Screen Shot 2020-11-20 at 2.29.29 pm.png

The pins in the wiring diagram are 2,1 and 8 and 7, 6 and 3.
If the diagram of the B22 is correct then the pins in the photo are 2,1 and 5 and 7,6 and 3.

I have been wiring to match the pin numbering on the B22 diagram - this is where my problem is. My wiring is arsed about because the unused pins are 4 and 5. In your picture they are located above each other - in the B22 diagram 4 and 5 are at opposite ends of the plug.

So from your photo it is now all clear - I have the white/ black trace, brown and light blue in the reverse order and one pin to the left. That is why nothing works! This also now matches the Haltech diagram up.

What really confused me for for a minute or three was the diagram shown at the bottom of your photo posts which was for the V6 not LS1.

I owe you some beers mate - I trust to report back tomorrow that I have it working.
 
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Jolls

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I read with great interest! My VZ LS1 Adventra is playing silly buugers atm. Runs fine, then randomly drops into 'Safe Mode'. Real handy at 100km/h with a truck on the bumper - Not! Can do this once in 300k's, or, 4 times in 20k's. Fault code does not pinpoint what is at fault - pedal or throttle body.
Good luck with your projrct!
Cheers
John

Hi John

Thanks - after months of effort and searching for correct pedal assemblies I think we have resolved the problem. an incorrect diagram in the original manual. If the idiots prior to me owning the beast had pulled the connector instead of cutting it off all would have been fine I am sure. Having pulled a couple of pedals apart I would expect that the wipers in the pedal are the most likely cause. If you look at Fu's photo of the internals further up this topic you will see what I mean.

Cheers

Jolls
 

Fu Manchu

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I got these for you this morning.

14B41759-E8A9-43DD-8BB4-D96F93B118A8.jpeg

The pedal part number.

I have already posted the picture of the pedal plug and wire positions in the plug, so that’s done.

A733DF03-2D79-40A0-B8DE-F0D73146DD6F.jpeg

Now the other end.

8732F761-F3F6-46C5-9F57-0218239D3E44.jpeg

The back of the plug (zoom in and you can make out the letters of the pin positions)

D9148D9F-9DCB-4010-8822-28DF5A51ADCB.jpeg

The other side

EA8640A6-BB83-48CD-A813-DF4BF9BE4609.jpeg

End view
 

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Fu Manchu

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AE985869-C12A-4F21-AE46-3577440F4702.jpeg

The TAC Module pin outs for the pedal plug loom. You can match these against the two photos of the plug that fits it.
 
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Fu Manchu

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It also just occurred to me the difference in the part numbers for the pedals might as simple as the alloy pedal finish that some SS had? Not all did.
 

lmoengnr

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Hi John

Thanks - after months of effort and searching for correct pedal assemblies I think we have resolved the problem. an incorrect diagram in the original manual. If the idiots prior to me owning the beast had pulled the connector instead of cutting it off all would have been fine I am sure. Having pulled a couple of pedals apart I would expect that the wipers in the pedal are the most likely cause. If you look at Fu's photo of the internals further up this topic you will see what I mean.

Cheers

Jolls
It wouldn't be the first time Holden factory manuals have been incorrect...
The VL manuals for the RB30 had the cam timing one tooth out on the belt...
 

Jolls

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Hi Fu

Thanks - your blood is worth bottling. The two pedals I have are 92183447 - so I have appear the right items even though Holden says they don't exist.

For those using this post in the future to try and diagnose your own problems.

I checked both pedals for operation before I tried them in the vehicle. Without any details it is difficult to tell if they were in spec; however, the readings are below for anyone that is interested in comparing to their pedals:

Pedal 1 - between pins 6 and 3 (5V ref and Pedal position sensor 1) - 4.75 kohm at 0% throttle 2.199 kohm at 100% throttle.
Pedal 2- between pins 6 and 3 (5V ref and Pedal position sensor 1) - 3.78 kohm at 0% throttle 2.04 kohm at 100% throttle.

Pedal 1 - between pins 1 and 8 (5V ref and Pedal position sensor 2) - 4.26 kohm at 0% throttle 1.836 kohm at 100% throttle.
Pedal 2- between pins 1 and 8 (5V ref and Pedal position sensor 2) - 3.257 kohm at 0% throttle 1.75 kohm at 100% throttle.

Pedal 1 - between pins 1 and 2 - 3.92 kohms, 2 and 8 - 2.131 kohms, 6 and 7 - 4.68 kohms and 3 and 7 - 2.199 kohms
Pedal 2 - between pins 1 and 2 - 2.79 kohms, 2 and 8 - 1.581 kohms, 6 and 7 - 3.46 kohms and 3 and 7 - 2.11 kohms

I was pretty comfortable that I had two working sensors in both pedals.

I threw them in the vehicle one after the other and tested them as per the manuial and had the same DTC codes from each test.

P1125 Accelerator Pedal Position System - output from the Powertrain Control Modulen (PCM). When this fault occurs the PCM sets a limp home mode of operation due to multiple APP sensor faults.

P2120 Accelerator Pedal Position Sensor 1 Range / Performance and P2125 Accelerator Pedal Position Sensor 2 Range / Performance. This fault occurs when the TACM determines the signal voltage of an APP sensor is outside the predetermined range. The Tech 2 had them reading about 0.12V with no change when the pedals were operated. Both pedals had exactly the same result - so I suspected, for the first time that the pedals and wiring are good. My suspiscions about the TACM earlier were beginning to haunt me.

It was then a process of following the diagnostics bouncing ball from the manual.

5V reference voltage from the TACM to the APP pins - 5.04V - within spec - tick!
Bridge 5V reference to APP sensor 1 - and read output with tech 2. PPS 1 - 0.12V PPS2 - 0.00V.
Change pedals - identical result. Fail - their reading should be of or about the input voltage of 5.04V.

The next step is to replace the TACM as bridging the wires should have provided an output around 5V.

I am now on the hunt for a replacement TACM to go with the new harness wiring.

I will report back once I have replaced the harness and the TACM.

For the technically minded - the circuit works as follows:

The TACM applies a separate 5 V reference circuit and low reference circuit to Accelerator Pedal Position (APP) sensor 1 and sensor 2. The APP sensors produce a signal voltage that represents the accelerator pedal position (increase in voltage proportionate to drop in resistance).
• The APP sensor 1 signal voltage increases from 1 V at rest position to greater than 4 V when the accelerator pedal is fully depressed.
• The APP sensor 2 signal voltage increases from 0.5 V at rest position to greater than 2 V when the accelerator pedal is fully depressed.
The TACM monitors and evaluates the APP sensors signal voltage along with other sensor inputs to determine the desired throttle opening. An APP sensor circuit DTC sets if the signal voltage of the APP sensor is outside the predetermined range.

More to follow.
 
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Jolls

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It also just occurred to me the difference in the part numbers for the pedals might as simple as the alloy pedal finish that some SS had? Not all did.
I have found a few people referencing the number on your pedal specifically to a Crewman. Now that we have some hard evidence I tend to think that is correct. The numbers for mine are different and I believe the sports pedal is the difference between the two. Can't imagine why Holden would have three of four part numbers for the same item in different vehicles. Sports pedal v pov pedal maybe.

It wouldn't be the first time Holden factory manuals have been incorrect...
The VL manuals for the RB30 had the cam timing one tooth out on the belt...
I'm sure that caused more drama than this issue has caused me - I feel for the poor buggers.
 

Jolls

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Hi All

To conclude this 7 month adventure - the beast lives! Despite the diagnostics pointing towards the TACM it wasn't. It was a faulty cable from the TACM to the accelerator pedal.

The cable arrived by post today - I was late home from work but just had to plug it in just in case. Sure as eggs the beast started and ran - sort of properly for the first time. I was amazed.

If you have followed this thread you will know that the cable had been cut and shut using a new connector that had been pinned as per the manual. As the manual's pin diagram was incorrect for the connector for 6 and 1/2 months I was unable to get the correct readings and the pedals I had purchased all seemed to be incorrect; because of course I was trying to align the readings from the pedals to what the manual indicated. So all of my musings did not make sense. Thanks to @Fu Manchu I was able to determine that the pinout in the manual did not match the pins running into his pedal - which was the same pedal I was using.

When I changed the pins to match I was able to finally get consistent DTC readings indicating that the accelerator pedal system was not well despite the cable now "functioning". Each individual cable had been tested, on numerous occasions, for continuity and pin to pin location. At my wits end I decided to replace the cable and the TACM. Replacing the cable, $135 from LSXtreme, has resolved the problem.

I checked the new and existing cables - pins in identical locations. All the joints were soldered and covered with heat shrink. I can only surmise that there was a dry joint in one of the cables that led to the out of range readings being thrown. The lesson to be learned here is - when working with computers do not cut and shut the loom. If you need to repair the loom run new cables from point to point and replace the connectors at both ends. Had I taken this approach - or purchased the cable from LSXtreme at the same time I purchased the ECM I would have been on the road about six months ago.

However, as a result of this trauma:
I now have a Tech 2 scan tool that is a real treat when working with the VZ,
I have managed to download a workshop manual - albeit with one incorrect diagram - thanks to @Fu Manchu,
I know a **** tin more about how the LS1 and drive by wire systems work than I ever did;
What I have found regarding pedal numbers, resistance readings and the dreaded incorrect B22 connector diagram is now documented.
I have learned a valuable lesson on computer based cars - should have stuck with FC's, and
I found this site which is just a brilliant resource.

I trust that sometime down the track that my experience will help someone else solve a problem.

Cheers n Beers

Jolls
 
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