THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

GRIFFIN · 2019-05-15 00:54:54

When I had my EGR valve problem, I had a mechanic friend of mine check the ECU for faults and his scanner said throttle pedal position sensor fault, which I ignored as I knew my fault was EGR related. Now everything is working fine, the pedal sensor fault is still there and it won't clear, also the engine management light has started randomly illuminating (mainly when it gets up to temperature) and then going out again.

I don't know if the problems are related but would like to locate the pedal sensor to try to find any poor connections or faults and fix them or replace the sensor. Can anyone tell me where the damned thing is? The only thing I can see in the on line manual is the charging lever potentiometer, which has slotted mounting holes. Is this another name for the pedal sensor? Or is it something different altogether? Also what effect would it have to undo the bolts and rotate the potentiometer? I think they are just called pots for short but what does this one do and could adjusting it help or even hinder my problem?

Cheers, Griff.

Last edited by GRIFFIN (2019-06-11 15:49:28)

Casper · 2019-05-15 16:04:40

I presumed this was it (pic) Is there not a Haynes manual for these vans. The bloody CD is next to hopeless.

vaz2121 · 2019-05-16 10:52:46

Casper wrote:

I presumed this was it (pic) Is there not a Haynes manual for these vans. The bloody CD is next to hopeless.
https://i.postimg.cc/VkdtdL0s/20190506-154546.jpg

Being that the DW8 has a cable rather than fly by wire set up I'd say what Casper's foto is pointing at...........

Other than a potentiometer measuring throttle angle in relation to fuel metering (I'd assume)...........

How that effects what control the ECU has over things in this basic form ?.........

I'll go along with your thoughts on treatment............

GRIFFIN · 2019-05-17 00:03:55

Hmmmmm yeah, mine is the DW8B but that is the same part. Problem is, I don't know if the throttle pedal position fault recorded by the ECU is what is making the engine management light come on intermittently or not.

I think I will get a Haynes manual, they do usually have a good fault finding section. In the meantime I'm gonna check all the connections and see If I can find any loose wires that may be causing the problem before I disturb or try to adjust the pot.

Cheers, Griff.

vaz2121 · 2019-05-17 07:50:28

I'm going to assume from your post that you've encountered a similar problem as I've had in past ................ (not van Thought)
"Engine light comes on and then goes out" ......... Leaves no trace of historic fault..................
The only way I caught mine was have the code reader plugged in while it was happening.............Not much of a revelation I admit........

It was noted there was a bit of a pattern to mine ........ {It illuminated usually when waiting at lights or junctions}

GRIFFIN · 2019-05-17 13:36:58

Hi Vaz,

Yes sounds very similar to mine, Do you remember what the fault was with yours?

I'm gonna check the cable tension to see if it may be too slack or too tight.

Then I'm gonna disconnect the potentiometer wiring to see if the light comes on all the time.

Cheers, Griff.

vaz2121 · 2019-05-18 09:05:28

GRIFFIN wrote:

sounds very similar to mine, Do you remember what the fault was with yours?

Bearing in mind it wasn't with the van and easily ten yrs ago with a 96 1.8 Vectra............

IIRC it was the MAF ......... as I do remember getting a cheepo off eBay which was on car for like a week ....... one robbed and fitted off another car and (He's nearly 40 now) The Boy giving the original MAF clean out with a squirt of either carb or brake cleaner and it running the rest of it days with the original......... Certainly with us with that MAF in it.......... But can't for life of me rememer exactly if it was one and same event.......

Sorry

GRIFFIN · 2019-05-18 13:05:51

Ah well that's good, when I first had my EGR problem I replaced the MAF sensor, as it ran slightly better when it was disconnected. Unfortunately that wasn't the problem so I put the old one back on after cleaning it and put the new one back in it's box. I'll put the new one on again and see if it helps, next time the light comes on.

I have noticed though, that since the weather has been colder this week the engine management light hasn't come on as often. Last week when the ambient temperature was higher it was coming on much more often and staying on for much longer.

Ah well. that's a couple of things to try out as soon as it stops raining sad
Cheers, Griff.

Last edited by GRIFFIN (2019-05-18 15:27:10)

GRIFFIN · 2019-05-19 00:45:47

Checked throttle cable today and it was way too slack, I did wonder why the pedal was so low and only had a very small amount of movement.

There was no retaining clip on the ribbed section of the cable, so it was all the way in. I didn't have the correct clip so I just opened up an R clip a little and that is doing the job. Haven't been far just yet so don't know what difference it will make but the engine management light has still come on again so it wasn't the cable tension causing that mad Bugger, will try the MAF sensor next.

GRIFFIN · 2019-05-20 01:37:35

MMMMMMMMM couple of things to report, today was warm again and engine management light was going on and off like a fairy light on a Christmas tree. Haven't had the chance to replace the MAF sensor yet but I did have a relatively long journey down to Yorkshire today. It would seem that, as one would expect, by adjusting the tension on the throttle cable my Scudo is now a little quicker. My top speed today has gone up from round 80mph to 90 mph, it would have probably been higher but I had to lift off in order to make the turn off on the motorway, sorry my mistake, I meant to say that I had reached the end of the runway on the private airfield where I was testing and had to lift off before I ran out of road.

Anyway, it may be worth checking but I dare guess that mine is not the only van that hasn't got this clip on the throttle cable. Of course there has got to be a down side to all of this but I'm pretty sure that next time I check my MPG it is not going to be in the high 30s, having said that the extra pedal travel has made the van much more driveable. The short travel on the throttle pedal made the accelerator feel like an on off switch, now the extra travel makes it feel much better.

Cheers, Griff.

Casper · 2019-05-20 17:58:58

I remember doing 90 in my last 1.9D thinking "This is scary" It was all over the place but this van seems much more stable and planted

90 (ish) must be the magic number

kenbw2 · 2019-05-20 23:32:42

90! How steep was the hill?

I took mine to Germany once and on a flat all I got was 80.

Looking at your temp gauge it was hardly even breaking a sweat.

Last edited by kenbw2 (2019-05-20 23:33:17)

GRIFFIN · 2019-05-20 23:46:45

Hahaha, I like the fact that you obviously had a passenger to take that photo for you while you were driving.

I finally got round to changing the MAF sensor today but as soon as I went out the Engine management light came on. Worth noting that the ambient temperature was about 18.5c today, again a warm day and the light comes on more often.

Well just gonna have to get my pall out with his ECU reader to see what faults come up this time. Also gonna try adjusting or changing the potentiometer as that was the fault that wouldn't go away. Been looking on Ebay for a Haynes manual today but they only seem to be for the 2007 onwards variant and also a one called the pocket manual but that doesn't include the DW8B engine, so it looks like the trial and error method mad wins again.

Cheers, Griff.

Casper · 2019-05-20 23:47:29

kenbw2 wrote:

90! How steep was the hill?
I took mine to Germany once and on a flat all I got was 80.
Looking at your temp gauge it was hardly even breaking a sweat.

That was the flat. As Griffin said pull the cable through using the clip. We used to have 306's as work cars what all came with slack cables when new. There is also a stopper on the floor under the throttle peddle. That should just screw out the floor. It was worth an extra few MPH also.

Casper · 2019-05-20 23:51:22

Bummer

https://haynes.com/en-gb/search?vrm=SE53CNY

GRIFFIN · 2019-05-23 01:09:05

Today I adjusted my throttle pedal position sensor. The manual says it's range is 0.2 to 4.9 V although it doesn't say what the Idle setting should be. the lowest setting I could get was around 1.22 V. Then I looked on the lever that the throttle cable is attached to and it says Lucas 2.45 volts on a little yellow plastic tab. So I thought what the hell, it must mean something or why put in there. So I fiddled around until the multi meter actually read 2.45 V.

Then I took the van out for a test run and it seemed quite smooth and free revving, much happiness, but the damned engine light still came on for a short time after five minutes. I am pretty sure that the engine light and the recorded TPS fault are two separate things.

Does anyone know if my assumption about the little yellow tab is correct?

I'll answer my own question now. I don't think it is correct because all the info I can find, leads me to believe that the resting voltage on the potentiometer should be round 1 volt.

I noticed that with the voltage set at 2.45 the throttle potentiometer seemed to be sending too big a signal to the ecu, as there was a little too much smoke coming out of the exhaust when the engine was under heavy load, going uphill etc.

I've since reset the potentiometer voltage to 1 volt and that has cured the problem.

Cheers, Griff.

Last edited by GRIFFIN (2019-08-01 23:23:40)

GRIFFIN · 2019-05-28 00:15:10

Van still going well, today the outside temperature dropped down to just over 10 degrees and as I expected, the engine management light didn't come on at all. It's really puzzling me as to why it only comes on when its warm outside? On the brighter side, my MoT is in October so it'll probably be fine as the temperature will have dropped back down by then big_smile

GRIFFIN · 2019-06-11 01:05:28

Well I finally cracked it. Having reset the throttle pedal sensor voltage and got rid of the fault on the engine management system, the orange light was still coming on especially when it was warm. Today I had the ecu scanned for faults and it came up with EGR valve fault, this did make sense, as when I first got the van one of the wires going to the EGR valve was broken and when I fixed it the light went out.

This evening I removed the connecter pictured above (which I had previously repaired) thinking my repair may have come loose. However, I discovered the conductor in the other wire had been stretched and broken inside the insulation.

Because it was still inside the insulator, the conductor wire was still touching sometimes, hence an intermittent fault. After a great deal of fiddling around I dismantled the connector, which came out easily as I had cut the wires previously and used bullet connectors to join it back onto the wiring harness, then soldered in a new piece of wire and sealed it with some heat shrink sleeving before reassembly. I guess the warmer weather must have made the insulation expand, pulling the conductor apart and causing the fault.

I would assume that someone has been trying to remove the connector by pulling on the wires, instead of undoing the clip and pulling on the connector body. In any event, I'm really glad that the problem is now fixed and because of that problem I discovered my throttle pedal sensor voltage was not adjusted correctly and fixed that too. I think that's what they call a win, win?

Cheers, Griff.

Last edited by GRIFFIN (2019-06-12 23:54:55)

kenbw2 · 2019-06-11 23:24:01

That's amazing - it's funny how we sometimes see patterns where there are none! I'm glad you got it fixed, it looks like a bugger of a diagnosis process.

GRIFFIN · 2019-07-31 12:38:00

I've been contacted about the method of testing the pedal sensor potentiometer output and as soon as I get chance I'll post some photos and an explanation of how to do it.

Cheers, Griff.

Stu-D · 2019-08-01 10:00:14

Thanks for this Griff.... Aside of the TPS issue I didn't get home till 4am as I think the stop sonenoid has gone, was driving fine, stopped to top up diesel, would not start again, turns over fine, glows getting 12v etc, the stop solenoid was very very hot (identified by the AA after I waited 3 hours on them), ah the joys of french and their crap electrics, I've been spoiled by my old VW's it seems, I forgot how temperamental french stuff could be!

-Stu

GRIFFIN · 2019-08-02 00:53:29

As promised, my guide on how to check and adjust the TPS. Mine is a DW8 B but it may be the same on other models.

First things first, get your tester and set it to 20v DC, take the Black earth or negative wire and clip it onto the negative side of the battery, like so.

Then locate the three wires coming out of the TPS and follow them round to the connector that they plug into. On the other side of the connector, you will see three wires coming out. We are interested in the middle one, this is the signal wire that goes to the ECU and tells it how far open the throttle is in order to regulate various functions of the engine and fuel system. Take about 30-40mm of a straightened out metal paper clip (not a plastic coated one, as it needs to conduct electricity) then push it well into the connector where the middle wire comes out and clip the red or live wire of your tester onto it, like so.

This will now allow us to measure the voltage coming out of the TPS. Turn on the ignition but don't start the engine or move the throttle pedal and at zero throttle you should get a reading of around 1 volt, sorry I cant be more precise but I can't find what the exact voltage should be. However if you get someone to sit in the cab and press the throttle pedal, the voltage should increase to around 4.5 - 4.9 volts at full throttle. If it doesn't give these approximate readings, you may need to adjust the potentiometer but before you do, you need to check that the throttle cable is adjusted properly and that the cable tensioning clip is in place that I mentioned (and pictured) earlier in this thread, because if your cable isn't tight enough the TPS won't move far enough to give full signal.

If you are happy that the cable is tight and you are indeed getting full throttle but you are not getting the correct voltage at no throttle or full throttle, then you may need to adjust the potentiometer which is pictured here.

Its made of black plastic with the word Lucas on it and you will see the two torx head screws holding it in place. If you loosen the screws you will be able to rotate the potentiometer, rotating it clockwise will increase the output signal voltage and anti-clockwise will decrease the voltage. When you have the output voltage where you want it, tighten the torx screws to keep it in place but don't over tighten, or you may strip the threads or crack the plastic body.

This is my zero throttle position reading.

And this is my full throttle reading. Sorry about the photo quality, it was getting dark and when I used the flash the reflection made it unreadable.

Before you make adjustments, remember that too low an output voltage and it may adversely affect the performance of the engine. Too high and it may increase the amount of fuel being delivered which may increase smoke and adversely affect fuel consumption. In any case, if you make a note of the zero throttle reading before you adjust the potentiometer, you can always return it back to its original setting and no harm is done.

Hope this is of some help.
Cheers, Griff.

Stu-D · 2019-08-07 00:31:34

Thanks for taking the time to post this Griffin, I'll re-approach once i get it running again, as per solenoid post lol smile

Best,
-Stu

TeddyMcB · 2023-03-29 19:38:19

Did any one ever figure out the purpose of the yellow tab with a voltage on it? There is a picture of it above. In Durhams van it was 2.45 volts. Where do you measure this voltage. It must be important as it is on all the Lucas injection pumps and they are different values on different vans.

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#1 2019-05-15 00:54:54

THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#2 2019-05-15 16:04:40

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#3 2019-05-16 10:52:46

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#4 2019-05-17 00:03:55

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#5 2019-05-17 07:50:28

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#6 2019-05-17 13:36:58

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#7 2019-05-18 09:05:28

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#8 2019-05-18 13:05:51

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#9 2019-05-19 00:45:47

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#10 2019-05-20 01:37:35

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#11 2019-05-20 17:58:58

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#12 2019-05-20 23:32:42

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#13 2019-05-20 23:46:45

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#14 2019-05-20 23:47:29

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#15 2019-05-20 23:51:22

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#16 2019-05-23 01:09:05

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#17 2019-05-28 00:15:10

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#18 2019-06-11 01:05:28

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#19 2019-06-11 23:24:01

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#20 2019-07-31 12:38:00

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#21 2019-08-01 10:00:14

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#22 2019-08-02 00:53:29

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#23 2019-08-07 00:31:34

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

#24 2023-03-29 19:38:19

Re: THROTTLE PEDAL POSITION SENSOR FAULT ON 2006 1.9 - FINALLY FIXED

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