Throttle / revs issue

[richardfrost]

This is an issue with my son's 2005 Jazz 1.4SE.

He was driving home last night the engine warning light, battery light and oil can light came on and the car was revving randomly, almost felt like there was no power. Limped the last few hundred yards then got the RAC out. Guy turned up and basically cleaned out the Throttle Body as best he could and said it might need cleaning again. I am not certain if he cleared the EMU code as I wasn't there.

Anyway, this morning, as he was setting off to work, the engine warning light is on again and on tickover, the engine revs are randomly going from 500 or so to 1500 or so on their own. Seems to be a lot worse when in reverse.

My son is reluctant to drive the car with the warning light on. He lives around 50 miles away from me so hard to pop round to help and I am not a mechanic or in any way able to fix cars.

It may just be that, having been cleaned, the car just needs to be driven for a while to settle down, but he is reluctant to do that with the warning light showing again, and the reversing thing was a bit weird.

The Jazz was serviced and MOT'd by Kwik Fit (Interim) three weeks ago. The EGR valve was checked within the last year. A brand new battery was fitted by the RAC around a month ago. The Jazz is mostly driven short 20 minute journeys around the city of York and does not often get a run of up to an hour.

We don't know York enough to know which are the reliable and good independent dealers. The main dealer I imagine will be expensive even for this sort of thing.

Have checked out these three threads...

http://clubjazz.org/forum/index.php?topic=8551.0 Fixing the niggles on a 14 year old SE Manual
http://clubjazz.org/forum/index.php?topic=8657.0 Jerking Jazz
http://clubjazz.org/forum/index.php?topic=7774.0 Jazz Stutter - Low rev, under load

My feeling would be to look at the following...
1. Throttle body again maybe.
2. By TG from the Jerking Jazz thread "Some Jazz have issues with the wiring leading to the electronic throttle body, this is tight in the conduit and often a green & yellow wire breaks.  This means that the signal between throttle pedal position and feedback from the throttle body position is interrupted.  This can be intermittent, and may only occur under certain conditions."
3. Spark plugs maybe?

Or maybe just take it for a drive and see if it clears.

Any thoughts? Anyone know a good independent garage in the York area?

Many thanks..

..Richard (and Rob)

[guest1372]

Sorry to hear about the problem, but his car hits the sweet spot for the throttle body wiring issue.  It seems that earlier cars with a cable throttle are OK, later cars have a slightly longer wire in the loom.  The 2004/5 cars have the tight wire that eventually fails under strain.  Removing / cleaning the throttle body might fix it for a while as the cable loom gets moved but the failure may reappear some time after.  I've spoken about this to several people but never fixed one myself although it does not seen too difficult if you know where/what to look for.

He's wise not to drive with the malfunction light on and a stuttering throttle.  I could pop round to Rob's with my code reader as I'm central York this week - that would confirm if #2 is the case.  I'm going to do a bit of research to see if the bit of loom at fault can be unclipped easily at both ends for an easy repair (or swap), or if it needs to be done in-situ.

Marshall's might be OK - they do occasionally surprise customers with a low bill, but there are many garages I could suggest that are probably alright although I'm reluctant to endorse any in public.
--
TG

[richardfrost]

Thanks very much for the response and offer to pop round TG.

At the moment, the plan is for Rob to take the car in the morning (Thursday) to Osbaldwick Motors, who have been recommended to us by a member of Rob's church.

I will point him at your suggestion so he can let them know to start there and will update this thread tomorrow night with what we know.

Many thanks again..

..Richard

[guest1372]

To aid those doing the research for cars built with an electronic throttle body by Bosch, here is a summary of what is known about the wiring fault which typically manifests itself as an intermittent stuttery or hesitant throttle pedal response which may sometimes only occur with the car in certain positions, under certain loads or at different temperatures.

Some research indicates that the typically faulty wire is the yellow/green 5v supply to the butterfly position feedback sensor on the throttle body served to pin 1 of it's 6 pin plug at the bottom of the unit.  There should be a steady 5v between pins 1 & 2 when the ignition is turned to position IG(II) and the cable loom leading to it is manipulated.

The cable forms part of the main wiring harness for the engine so is not easily removed and should be repaired in situ.  The cable at the top of the throttle body is not involved and supplies a different sensor.  Feedback indicates that the break is at the T junction in the conduits closest to the throttle body.  It may of course be a different wire, somewhere else, or another fault entirely.   

Throttle body connector (6pin) is wired to the ECM like this: 
The reason for the strikethough is the wiring diagram contradicts itself on a subsequent page.

Pin   Cable    Function                              Levels when key is in IG(II)
ECM connector 3 (52pin)
 4    YEL/GRN  VCC3 (Voltage supply to sensor)       5v
16    YEL/BLU  VCC2 (Voltage supply to sensor)       5v
29    GRN/BLK  SG3 (Sensor ground)                   0v
48    GRN/BLK  SG5 (Sensor ground)                   0v
36    BLU      TPSA (Throttle position sensor A)     Throttle closed 0.1v / fully open 4.7v
49    YEL      TPSB (Throttle position sensor B)     Throttle closed 0.1v / fully open 4.9v

ECM connector 5 (9pin)
 1    RED      ETC1 (Electronic throttle control 1)
 2    GRN      ETC2 (Electronic throttle control 2)


The throttle pedal sensor is also wired to the ECM

ECM connector 3 (52pin)
34    GRN      APSA (Accelerator pedal position sensor A) Released 0.6v / pressed 4.1v
50    RED      APSB (Accelerator pedal position sensor B) Released 0.2v / pressed 2.3v


--
TG

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[richardfrost]

Wow, thanks for this information TG.

The garage, which by the way does not want to charge us for over an hour's worth of investigation, does not think it is this wiring issue. Four fault codes came up on their computer (might have got the descriptions wrong)...

007-05 - Throttle Value Pedal Position Sensor B
007-08 - Throttle Value Pedal Position Sensor A
040-12 - Throttle Value Control Performance Manual(?) Faulty
040-13 - Throttle Value Control Performance Actuator

These are not Honda codes but they seem to point the finger at the Potentiometer or Throttle Body itself but the guy is concerned that are not specific enough and suggests we go to Honda. Honda parts are £285 + VAT and £633 + VAT so we don't really want to go randomly replacing parts if we can't figure out where to start.

So it looks like I need to sort out a tow to Honda and a £75 fee for them to look up the exact problem with their computer.

[guest1372]

The OBDII codes that can be picked up with a basic reader are P0122, P0123, P0222, P2123 which all indicate a variance between the throttle pedal position and the expected throttle butterfly position. 

There have been cases of people buying new TBs without fixing the issue, incidentally reclaimed parts are <£50.  I'd put £10 on it being the wiring to the sensor rather than the sensor in the TB itself. 

I would check the standard codes and see if 5v can be confidently maintained between pins 1 & 2 of the TB plug before going any further. 

PM me if I can help any further, not doing anything tonight but need to get out of my suit first.
--
TG

[richardfrost]

You was bang on right TG. John at a Osbaldwick motors found the faulty wire and bridged the break. Repaired for under £100. Mostly labour finding and fixing. Thank you so much.

[jaytee]

thank you so much i had the same issues . a new throttle body would have cost 800 . armed with this info from the forum the yellow green wire was found to be broken . auto electrian rewired it . total cost £85 .

[richardfrost]

thank you so much i had the same issues . a new throttle body would have cost 800 . armed with this info from the forum the yellow green wire was found to be broken . auto electrian rewired it . total cost £85 .

So good to know this thread helped you jayvee. TG seems to have left the forum since this original issue arose but he was supremely helpful to us, including his offer to pop round and test the wiring.

Happy to report that three years on and the fix is still good. Car is on around 120,000 miles now and is on loan to my other son's girlfriend.

[Darryl]

This is an interesting and very useful thread which I intend saving for future reference.

Is there any chance that someone could post a couple of photos indicating the exact  area concerned where this issue typically arises.

Thanks Darryl

[Jocko]

Photos on this post:
https://clubjazz.org/forum/index.php?topic=9100.msg48093#msg48093

[Darryl]

Thanks for that Jocko.

[jaytee]

there is also a youtube video where the guy points to the location of the wire after he he fixed this. just type honda jazz throttle body . i found this very helpfull. hope this helps.

[Darryl]

[Naren]

Hi
I have this problem and I have replaced the throttle body but still have the engine light still come on. I do think that it is the yellow or green wire.... 
can you recommend someone in the Solihull area who can check and repair this issue.?
Thanks
Naren