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Omega Help Area => Omega General Help => Topic started by: mrjimbo on 02 December 2010, 12:52:20

Title: Fault codes
Post by: mrjimbo on 02 December 2010, 12:52:20
I did a journey of 279miles yesterday and used 51.00 litres of fuel( 24.87mpg)all on motorway and dual carriageway and i kept ot a steady 75mph on the motorway and 55mph on the dual carriageway. I was on the move all the time, no queuing anywhere, only slowed to 50mph once on the M6 in the roadworks at Gravely Hill.

I've just been out and done the paper clip test and it read as follows -

Engine not running

31   No Engine RPM Signal
71   Intake Air Temperature Voltage High
73   Mass Air Flow Sensor Voltage Low
74   Mass Air Flow Sensor Voltage High

Engine running
71   Intake Air Temperature Voltage High
73   Mass Air Flow Sensor Voltage Low
74   Mass Air Flow Sensor Voltage High

Engine runs smoothely, no misfires etc and idles smoothely aswell. 

Any thoughts on this ?


Title: Re: Fault codes
Post by: Jimbob on 02 December 2010, 13:06:43
disconnect, then clean the maf connector, ensure its fully home when you put it back.

Have you got code deleting facilities?

31 is normal with engine off  :y
Title: Re: Fault codes
Post by: mrjimbo on 02 December 2010, 13:19:55
Cheers Jimbob  :y

I understand the 31 code but not sure about the 71,73 and 74 codes though as it's not showing any signs of being faulty, no engine light etc.

Whats the best stuff to clean the connector with ?

I don't have anything to clear the codes with so does that mean a set number of clean starts to clear ?
Title: Re: Fault codes
Post by: Brikhead on 02 December 2010, 13:56:26
Quote
Whats the best stuff to clean the connector with ?

I don't have anything to clear the codes with so does that mean a set number of clean starts to clear ?

You can buy electrical switch/contact cleaner if you'd prefer not to use WD-40.

You can usually reset the e.c.u. by disconnecting the cars battery overnight, be aware you will need the radio codes if you try this...
Title: Re: Fault codes
Post by: mrjimbo on 02 December 2010, 14:02:34
OK i'll try that a bit later, just waiting for the plumber, the central heating pumps decided to pack up  >:(
Title: Re: Fault codes
Post by: Jimbob on 02 December 2010, 14:04:03
Yes, switch cleaner, wd40 if really nothing better about

20-30 clean starts will remove

removing battery just resets learned data, not fault codes which is in non volitile memory, so dont bother with that.
Title: Re: Fault codes
Post by: mrjimbo on 02 December 2010, 14:37:08
Switch cleaner, is that the same stuff as Brake cleaner or is it differant stuff ?
Title: Re: Fault codes
Post by: Jimbob on 02 December 2010, 14:42:10
Quote
Switch cleaner, is that the same stuff as Brake cleaner or is it differant stuff ?


very different

switch / contact cleaner is the stuff.

you could just pull/push a few times, that will likely improve the connection
Title: Re: Fault codes
Post by: mrjimbo on 02 December 2010, 15:07:31
OK i'll try and get some switch/contact cleaner   :y
Title: Re: Fault codes
Post by: Jimbob on 02 December 2010, 15:09:35
just disconnect / reconnect 1st, may do the trick.

It may be a deeper issue than connection anyway, but its a starting point.
Title: Re: Fault codes
Post by: mrjimbo on 02 December 2010, 22:45:18
Is there any way of testing the MAF sensor other than just unpluging it, can it be tested for resistance etc with a meter ?

Same with the Air Intake Temperature sensor ?

Don't really want to go and buy a MAF sensor to find the problem lies somewhere else.
Title: Re: Fault codes
Post by: mrjimbo on 03 December 2010, 10:55:38
Been out and cleaned the connectors on the MAF sensor and Intake Air Temperature sensor and done 30+ starts and codes 71,73 and 74 have now gone  :)

but now have 21,

21   Throttle Position Sensor (TPS) Voltage High

Off out to clean that now  >:(   outside temperature display is saying -3 and trying to snow again   >:(
Title: Re: Fault codes
Post by: Jimbob on 03 December 2010, 11:02:40
May be a result of all those starts, battery voltage will be affected by that lot, id leave it alone and see how it goes.
Title: Re: Fault codes
Post by: mrjimbo on 03 December 2010, 11:12:10
I did some of the starts on the drive then some more when i went up the town and did another 15 or so when i went down the trading estate and did the long way home so the battery should be OK   :y
Title: Re: Fault codes
Post by: TheBoy on 03 December 2010, 11:19:15
Quote
Quote
You can usually reset the e.c.u. by disconnecting the cars battery overnight, be aware you will need the radio codes if you try this...
*cough* cobblers *cough*

This is a Motronic ECU ;)
Title: Re: Fault codes
Post by: TheBoy on 03 December 2010, 11:21:13
That MAF is going to need a decent code reader on it to be sure.  However, my initial feeling, given that its reading high and low, is connector.


As JB says, run it about for a few days, see what comes back :y
Title: Re: Fault codes
Post by: mrjimbo on 03 December 2010, 11:28:06
I,ve got rid of the codes for the Air Intake Temp and the MAF sensor but 21 has popped up now

21   Throttle Position Sensor (TPS) Voltage High

so i've just cleaned the connector on the TPS and will report back later   ;)
Title: Re: Fault codes
Post by: mrjimbo on 03 December 2010, 11:59:54
All codes now gone   :y

I'll check again in a couple of days, just to be sure but all seems OK now.
Just hope the mpg improves  :o
Title: Re: Fault codes
Post by: TheBoy on 03 December 2010, 12:10:25
Could be worse - my MPG dropped to 17mpg :o :o
Title: Re: Fault codes
Post by: mrjimbo on 03 December 2010, 12:23:59
I don't normally take much notice of the mpg as i do more short journeys than longer ones at the moment but i know that when i checked in the summer it went down to 28mpg and i couldn't really find a reason for it, but i recently changed the cambelt and the mpg did improve but never managed to get a chance to find out how much it had improved and there were no codes present after doing the cambelt and i checked the codes again last weekend and they were all clear then aswell but when i only got 24mpg on a 280 mile journey i wasn't impressed.

All clear now though. Got a longish journey tomorrow so i'll check mpg then and see if it's improved   :y
Title: Re: Fault codes
Post by: mrjimbo on 04 December 2010, 18:45:03
Right, just back from Brum which was a round trip of 164miles and used 28.25lt of fuel which works out at 26.4mpg so the fuel consumption has improved slightly which is good but not brilliant seeing as it was all motorway and dual carriageway.

When i came off the dual carriageway close to home the engine symbol came on as i came down the slip road. It went out after about 1/4mile and hasn't come on again since. It starts and runs OK and idles OK. I've just been out and paperclipped it and it's showing code 16

16   Knock Signal Circuit 1

any ideas what thats all about ?