97 5ltr VT code 49

Wiring diagrams and questions
GTS308
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1997 HBD VT 5ltr

97 5ltr VT code 49

Post by GTS308 »

Hello all, I bought a 97 Holden by Design 5ltr VT off my brother inlaw late last year it had only done 68,000 from new and was spotless. It had just been fitted with extractors and high flow cats and exhaust a month prior to me buying it. The brother inlaw hardly drove the car only clocking up 20,000ks since he baught it in 2002 as he had a company car..I noticed when driving it home some 180ks that it had less power than my 5ltr VR which I had just sold and put it down to the car being rearly driven and when it was, it was babied. (May needed to be run in a bit..lol)

Anyway about a month after I bought the car it stoped, local mechanic put it down to a voltage spike so new regulator was fitted with a new cam/crank angle sensor. Apon starting the car and taking it for a test run I was told the coil was faulty so it was replaced. The new coil lasted 5 minutes then that died so another one was fitted..I was not happy with the way the car ran as it had a intermitent miss a idol and felt like it ws surging..So plugs, leads, fuel filter were changed with no difference being found. I decided to take it to the local Holden dealer so they could use their Computer to sus out the problem and it came up with code 49. Making the car pulse injected not sequential.

The cam/crank angle sensor was replaced again but did not fix the problem, a new distributor was fitted this did not fix the problem either. So the ignition module was replaced new leads and plugs fitted again all earths and conections were checked, wiring from the distributor to the ignition module and the PCM was bypassed and new wires run..Still no joy..
New PCM and Memcal fitted, Holden technical boffins suggested a new engine wiring harness ($350) which was fitted and you guessed it still threw code 49 just running in the workshop. I disconected the wire to the tacho in hope it may have been the cause..nope!

In a last ditch effort we fitted a genuine holden VT coil and it ran like a dream in the workshop but as soon as you hit a bump it throws the code again.
Now as everything under the bonnet has been removed replaced checked several times do you think the problem may be under the dash on the drivers side between the BCM and the PCM?
Loose/bare wire or something?

Only reason I ask is when the brother inlaw bought the car he was given a service report from the dealer. OIl change, filter, machine brakes ect but it also had on the sheet the supply and fitting of a new steering column $785. The brother inlaw did not bother to ask why they fitted this before he bought the car and as it had only 45,000ks on the clock I have no idea why either...Also on top of the work sheet it had 5 codes and yep you guessed it one was code 49...So I think the car had this fault either when it was traded or after they fitted the steering column, either way I think they just cleared the codes and pushed it out the door as none of the codes would make the engine management light come on, and with code 49 it just reverts to pulse injection not sequential. So the average city driver would probably not even notice...

So anyone had this problem before?...... We have had a oscilloscope reading the cam sensor and it shows no problem but the hand held Holden computer comes up with cam angle sensor missing..
Is there anyway to reprogram the memcal to ignore code 49 or for it take no action so to speak?
Or should I, just to be certain that this is the dearest VT in Australia, replace the BCM and wiring under the dash or have it stuffed so it can be displayed in the Holden museum?
Its been in the worshop for 5 months now I want my car back..

Look forward to your replies...Cheers! :cry:
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Jayme
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Re: 97 5ltr VT code 49

Post by Jayme »

Here is a section about DTC 49
VT_DTC_49.pdf
(59.09 KiB) Downloaded 763 times
so from what ive read it sets if the engine doesnt receive exactly 1 cam sensor pulse for 8 crankshaft reference pulses less than 8 times out of 10 complete cycles.
so you seem to have replaced everything that directly influences this. interference in the reference lines from ign module to ecu could cause it but you would probably also notice a miss, the only other thing that I think could influence it assuming everything you have replaced is good, is a dodgy power wire but again, you would hear a miss if that was the case. maybe your enging has a missing earth strap to the body causing funky ground loops? you certainly have a funky one there mate.
kojab
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Re: 97 5ltr VT code 49

Post by kojab »

A few things I don't understand here.

The 5L VT engine does not use a cam/crank angle sensor. The cam signal comes from within the distributor. Maybe some one has fitted an earlier dizzy that has no cam sensor output.
I thought Code 48 was cam signal missing.

Dick
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Jayme
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Re: 97 5ltr VT code 49

Post by Jayme »

yeah 48 is cam sensor missing. 49 is cam sensor intermittent. so only having 49 by itself means it is getting a cam sensor signal but not all the time. maybe the doofuses at holden told you they reaplced something but didnt really. some idiot apprentice maybe LOL cant count out the human error....
GTS308
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cars: 1973 308 GTS4 HQ Monaro
1974 HQ Kingswood factory V8 4 speed
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1997 HBD VT 5ltr

Re: 97 5ltr VT code 49

Post by GTS308 »

No the Holden guys are not pulling my leg. The business is owned by a friend of mine.

The 5 ltr VT had both a cam and crank angle sensor on the mounting plate inside the distributor. One was for timing the other for the injection as the VT was the only sequential injected 5ltr.
Yes sorry I did meen intermittent........ Until the genuine Holden coil was fitted it would idle fine but as soon as the revs increased it threw the code. Now it is running sweet but we took it for a test and ran over the lumpy yellow road dividers at slow speed on pupose and the bump throws the code...So maybe it is a earth issue more so than a short or power issue.
I might go in agian early next week and starting at the battery recheck all the earths and maybe run a extra body earth and put one from the engine mount to the body as well, cant hurt I guess.
I thought maybe something was damaged under the dash when the new column was fitted, but I cant think why it would be only affecting the cam angle sensor.

Even the Tech boffins at Holden HQ have no answers...We build em you fix em ..lol

I will post the final outcome when its found, just so if anyone else has the same problem they might be able to fix theirs...
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Doctor Bob
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Re: 97 5ltr VT code 49

Post by Doctor Bob »

The Circuit is pretty simple, the fault WILL be in this circuit.
The hard part is being an intermittant fault.
all i can suggest is DO NOT fit new earths or replace wiring, chances are you will create more issues.

follow the diagnostic exactly, if it is not an int code you will find the fault.

Disclaimer:
this is only my opinion, backed by more years in Holden elec diagnostics than i care to remember.

Cheers Rob
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GTS308
Posts: 16
Joined: Thu Apr 07, 2011 3:51 am
cars: 1973 308 GTS4 HQ Monaro
1974 HQ Kingswood factory V8 4 speed
1952 202 powered chopped top Morris Minor two door.
1997 HBD VT 5ltr

Re: 97 5ltr VT code 49

Post by GTS308 »

Thanks Rob.. I can assure you that all the checks where done as per Holdens tech manual like you have shown.
But with the crank sensor, coil and Ignition module being replaced not once but three times with new units and the PCM, memcal and wiring harness being replaced with new items, it only leaves "to me anyway" the answer is either power or earth....Unless there is some wire from another part of the car that is causing interference or giving a faulse signal..

As I said earlier it has now gotten to the point that its fine until it hits a bump then it throws the code...

Cheers...
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Doctor Bob
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Re: 97 5ltr VT code 49

Post by Doctor Bob »

just a thought, check the supply to the EFI relay under the bonnet, i have seen an issue with the connector in the relay block, its a double ended female spade terminal from the power bus bar to the relay. i have had to lift the fusebox & solder the bottom end of this to the busbar.

Rob
GTS308
Posts: 16
Joined: Thu Apr 07, 2011 3:51 am
cars: 1973 308 GTS4 HQ Monaro
1974 HQ Kingswood factory V8 4 speed
1952 202 powered chopped top Morris Minor two door.
1997 HBD VT 5ltr

Re: 97 5ltr VT code 49

Post by GTS308 »

OK, Cheers Rob I shall have a look....

Ok back......... removed fuse block re-soldered ends on orange/yellow wire from relay to fuse (Injection) Other side of relay + is a bus bar type plate..this is all good..Banged the crap out of it with no voltage drop.
Mechanic informs me that when the scope was on the wire from cam/sensor to D3 on PCM the 5volt power supply would spike then throw the code.?????????

Ran the car without the alternator so no voltage spike from charging...D3, 5 volt line shows a distinct spike just before throwing the code...
So what item can cause this when being banged/bumped...I thought the 5 volt reference was set and could not increase?

When to the local wrecker and they lent me a VT 5ltr auto BCM same part number as mine with no key head..So tomorrow will access the GMH mainframe and find the code for this BCM via the cars Vin No.
Will reprogram a new key and fit the BCM...Have no idea if this will have any effect on fixing the problem but hell it cant be any worse than what I have at the moment..
UCMatt
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Re: 97 5ltr VT code 49

Post by UCMatt »

Do you see a corresponding spike on the B+ supply to the distributor sensors?
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