Mystery of the HOLD light!

Technical questions and answers about the Mazda Bongo

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progroup

Mystery of the HOLD light!

Post by progroup » Sun Jan 15, 2012 11:59 pm

I trialed Geoff's Diagnostic Connector notes on determining Engine/AT codes.

My auto electrics guru from next door came over and helped me decipher the notes into practical action steps. Neither of us could figure out the source of the flashing HOLD light nor get the +B/GND or TEN & TAT pins to flash an LED light.

I am miffed beyond what you can imagine!

Two weeks after installing the rebuilt FIP, I still cannot solve the HOLD light. While flashing, the gearbox does not downshift or hold any gear.

Any other ideas?
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Velocette
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Re: Mystery of the HOLD light!

Post by Velocette » Mon Jan 16, 2012 12:38 am

progroup wrote:I trialed Geoff's Diagnostic Connector notes on determining Engine/AT codes.

My auto electrics guru from next door came over and helped me decipher the notes into practical action steps. Neither of us could figure out the source of the flashing HOLD light nor get the +B/GND or TEN & TAT pins to flash an LED light.

I am miffed beyond what you can imagine!

Two weeks after installing the rebuilt FIP, I still cannot solve the HOLD light. While flashing, the gearbox does not downshift or hold any gear.

Any other ideas?
I believe 3 or 5 starts cancels the fault from memory. If it is stilashing it should flash a codeyou short the relevant pins. Hold light vfor transmission and glow plug liht for engine I believe. mine was the throttle position pot. I think it is one of those things that benefits from replacement if it is getting on in mileage and years as the track gets worn in the commenest throttle positions. Mine was transformed after replacement.


when
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progroup

Re: Mystery of the HOLD light!

Post by progroup » Mon Jan 16, 2012 1:02 am

3 to 5 starts? Or do you mean cycles of the ignition?

With out the code(s); I am only guessing if TPS or Idle s/w, gearbox sensor, etc. The TPS alone is $160 'ish new or $30 used. The ECU is $130+ new on eBay [although I strongly doubt that!] or $50 used.

Best to figure out before spending any more money.
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Re: Mystery of the HOLD light!

Post by Northern Bongolow » Mon Jan 16, 2012 1:10 am

did you test the values you should be getting at the tps, they are in the manual.
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Re: Mystery of the HOLD light!

Post by Northern Bongolow » Mon Jan 16, 2012 1:13 am

also, if yes and its not ok, pm The Great Pretender (mel), he may hold the answer to a cheaper alternative part 8)
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Re: Mystery of the HOLD light!

Post by dandywarhol » Mon Jan 16, 2012 3:52 pm

From memory, you disconnect the battery and press the brake pedal for around 5 seconds - this clears the fault codes. pressing the brake pedal illuminates the brake lights and "drains" any residual current in the ECU.

Thats why many cars now illuminate the brake lights when you press the pedal with the ignition key out.
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progroup

Re: Mystery of the HOLD light!

Post by progroup » Mon Jan 16, 2012 4:42 pm

Northern Bongolow wrote:did you test the values you should be getting at the tps, they are in the manual.
For sure! I performed the tests as per the manual. Couldn't get any voltage from the TPS-to-ECU-pin#2i. Should be between 1.3 and 4.2 volts I believe.
progroup

Re: Mystery of the HOLD light!

Post by progroup » Mon Jan 16, 2012 4:44 pm

Northern Bongolow wrote:also, if yes and its not ok, pm The Great Pretender (mel), he may hold the answer to a cheaper alternative part 8)
Yes I will; thanks for the tip!
Dave
progroup

Re: Mystery of the HOLD light!

Post by progroup » Mon Jan 16, 2012 5:18 pm

dandywarhol wrote:From memory, you disconnect the battery and press the brake pedal for around 5 seconds - this clears the fault codes. pressing the brake pedal illuminates the brake lights and "drains" any residual current in the ECU.

Thats why many cars now illuminate the brake lights when you press the pedal with the ignition key out.
Yes, I have done that several times. What I am miffed about is why the HOLD light flashes immediately after I 'touch' the thottle. After clearing the codes; I start the engine and as it idles, no HOLD light until I touch the linkage or idle switch is open.

We spent a good few hours by-the-book. My Bongo's diagnostic connector has vacant pins or blanks due to it's model/year. I have a +B pin, a GND, a FAT, a TEN. However, despite jumping these few pins with a custom LED light, the LED does NOT FLASH probably because there aren't any trouble codes to present.

If no codes are visable by-the-book, why else would the HOLD light flash at approximately one second intervals [ON/OFF/ON...]?

When the vehicle is running; the HOLD 'button' on the shifter does NOT function. If the ignition is ON and NOT running; the HOLD button works and the dash shows as per normal [the HOLD light is ON consistently!]. Weird, eh?

Anyway, I was anticipating a code 12 pointing to the TPS. Now I am uncertain! Maybe it will be in the gearbox? I am tenacious and probably will not give up. But at the end of the day I think I will need some parts. they are expensive parts by the time I get them here in Canada.

My Japanese friend is coming March 1~14 and confirmed he would bring all the soft electrical parts I would need. but I don't want to wait quite that long!

Next step would be to PM the Great Pretender I guess.

Having said all this, I sincerely thank you all for the continued support. :)

Cheers,
Dave
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Re: Mystery of the HOLD light!

Post by dandywarhol » Mon Jan 16, 2012 5:33 pm

Now!!!! somewhere from my distant past a friend had a problem with the hold light coming on and we traced it to a bad conection to the coolant temperature plug in the middle of the cyl. head. There's a short wiring loom from the main loom to the sensor and this had a bad connection - the gearbox changes are dependant on coolant temperature and this poor connection caused the hold light to come on and the 'box not to go higher than third. It's just possible your throttle cable is touching the loom?????
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Re: Mystery of the HOLD light!

Post by progroup » Mon Jan 16, 2012 5:48 pm

dandywarhol wrote:Now!!!! somewhere from my distant past a friend had a problem with the hold light coming on and we traced it to a bad conection to the coolant temperature plug in the middle of the cyl. head. There's a short wiring loom from the main loom to the sensor and this had a bad connection - the gearbox changes are dependant on coolant temperature and this poor connection caused the hold light to come on and the 'box not to go higher than third. It's just possible your throttle cable is touching the loom?????
Excellent! I will check this first off. Makes sense to me as I had replaced the sensor with a new one during the head replacement. I still have the old one as well. It was suggested back when to replace this with a new head.

I will let you know what I find...
Many thanks, Dave
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Re: Mystery of the HOLD light!

Post by g8dhe » Mon Jan 16, 2012 6:10 pm

If you used an LED was it a standard Red/Green/Yellow one if so did you check that you had the LED connected the right way around ? They are directional and won't light if reversed.
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Re: Mystery of the HOLD light!

Post by westonwarrior » Mon Jan 16, 2012 6:59 pm

the fault code show via the hold light not an led

When mine was playing up I just shorted the terminals in the fact sheet and the hold light flashed a sequence.

This is the first I have heard of a led being used

the glow plug light flashing may work this way for engine faults but the tps shows via the hold light code 12
progroup

Re: Mystery of the HOLD light!

Post by progroup » Mon Jan 16, 2012 7:18 pm

g8dhe wrote:If you used an LED was it a standard Red/Green/Yellow one if so did you check that you had the LED connected the right way around ? They are directional and won't light if reversed.
Yes a 'green' one and pre-tested the right way around :wink:
progroup

Re: Mystery of the HOLD light!

Post by progroup » Mon Jan 16, 2012 7:22 pm

westonwarrior wrote:the fault code show via the hold light not an led

When mine was playing up I just shorted the terminals in the fact sheet and the hold light flashed a sequence.

This is the first I have heard of a led being used

the glow plug light flashing may work this way for engine faults but the tps shows via the hold light code 12
Okay, if that's true, the HOLD light flashes in 1 sec intervals with no pausing. Does that likely mean a code 12? My original thought was the TPS or code 12, but I can't prove it... at the least, an educated guess until a new part can be fitted.
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