PDA

View Full Version : Scangauge II and cancelling codes


Andyandyandy
02-19-2013, 09:55 PM
I bought a Scangauge II a while back and have found it useful, although I haven't had the time to learn the finer points of fuel consumption data and all that. My main incentive for buying it was to be able to clear the CEL which comes on periodically due to a couple of glow plug circuits that I am putting off until warmer weather. Typically the light would stay off for a week or so after the codes were cleared by the Scangauge. Lately though the interval has been getting shorter. Twice yesterday, and three or four times today. Today's driving consisted of a few very short trips, maybe a mile each, separated by an hour or two. I don't think the temp. gauge ever moved off the peg.

Any ideas why the interval is getting shorter? Is the ECU or the Scanguage getting impatient with me for not dealing with the problem? Has anyone else seen this?

I just remembered that yesterday when I went to clear the codes it had a message like 'not reporting' or something to that effect, which I'd never seen before or since. The CEL did go out as usual though, until it came on again this morning.

autostaretx
02-19-2013, 10:10 PM
What error code was the ScanGauge reporting before you clear it/them?

That would perhaps give us a hint as to what the root problem(s) really are...

--dick

Andyandyandy
02-19-2013, 11:54 PM
Hi Dick, the codes are P071 and P073. Open glow plug circuits on #1 and 3 cylinders. No big deal as it starts fine even in the cold but I'll wait until spring to change the plugs and probably modify the module to external fuses. I'm just curious as to why the light is coming on sooner after being cancelled. It's mostly a minor annoyance; the van starts and runs just fine.

Andy

Andyandyandy
02-23-2013, 02:28 PM
Today the light came on and I cancelled the codes. Next startup the same thing happened. Any ideas?

Andy

dodger413
02-23-2013, 02:42 PM
until you fix (replace) the problems (glowplugs) the light will keep returning and you will keep cancelling them.

just cancelling the CEL light doesn't cure the problem. Your Sprinter is telling you something is wrong that needs to be fixed. fix it. and the CEL lights will go away.

keep doing what you are doing, and we will continue to see posts from you asking the same question over and over again.

Andyandyandy
02-23-2013, 02:58 PM
No need to be condescending. I know what the problem is with the glow plugs. My question was to do with why the light is coming on sooner after having been cancelled.

surlyoldbill
02-23-2013, 03:11 PM
You should expect the light to come on every time the ECU senses a problem. I'm surprised it doesn't come on every time you have a cold start after clearing it.
I have a glowplug issue that I'm waiting until Spring and longer days to fix. The GP light comes on with every cold start, but doesn't come one with a hot start. The CEL is on from a diferent matter, I think.

icarus
02-23-2013, 03:27 PM
It is pretty simple...it is telling you something is broken, because...something's broken! As has been said, just clearing the code won't fix what's broken. If you are conviced that you have a GP issue (why are you convinced of that, MB Scan) you re probably ter off not bothering to clear the code, as you may e clearing other codes that MB could use to diagnose what (else?) maye wrong.

Icarus

autostaretx
02-23-2013, 07:57 PM
until you fix (replace) the problems (glowplugs) the light will keep returning
..that's true.. and given your codes, it's either the glowplugs being open (an ohmmeter could test that: resistance higher than 7 ohms, possibly infinite) or the glow plug module's internal fuse links are blown (open and visually inspect them). If the module's "fuses" are blown, that's a pretty good hint that the glow plugs themselves may be short-circuiting (i.e. too low a resistance, hence the fuse/link blew). In which case simply repairing the module will see it blow those fuses/links again.
You can test the glow plugs for a short with a good ohmmeter, willing to detect the subtle difference between about 1 ohm (good) and less than half an ohm (approaching bad).

And, you could be double unlucky and have one open plug, one shorted plug, and the module with just the shorted plug's link blown...

The "used to only occasionally show the light" changing to "the light every time" probably means that a part was in the process of failing, such as one plug gradually raising in resistance ... from "detectable sometimes" to "definitely bad"
--dick

surlyoldbill
02-23-2013, 09:42 PM
..that's true.. and given your codes, it's either the glowplugs being open (an ohmmeter could test that: resistance higher than 7 ohms, possibly infinite) or the glow plug module's internal fuse links are blown (open and visually inspect them). If the module's "fuses" are blown, that's a pretty good hint that the glow plugs themselves may be short-circuiting (i.e. too low a resistance, hence the fuse/link blew). In which case simply repairing the module will see it blow those fuses/links again.
You can test the glow plugs for a short with a good ohmmeter, willing to detect the subtle difference between about 1 ohm (good) and less than half an ohm (approaching bad).

And, you could be double unlucky and have one open plug, one shorted plug, and the module with just the shorted plug's link blown...

The "used to only occasionally show the light" changing to "the light every time" probably means that a part was in the process of failing, such as one plug gradually raising in resistance ... from "detectable sometimes" to "definitely bad"
--dick

Dick, when you refer to testing the GPs, are those ohm readings while installed in the head (connector tip to engine ground), or when removed (ohm between case and tip)?

autostaretx
02-23-2013, 11:34 PM
Dick, when you refer to testing the GPs, are those ohm readings while installed in the head (connector tip to engine ground), or when removed (ohm between case and tip)?
I was picturing the test with the plug still in the engine (why not?)

Therefore plug tip to engine head.

You could also test from the glow plug module connector to the glow plug tips, too... in case one of the wires had broken.

It wouldn't hurt to check the engine's ground strap, too. (resistance from engine to Sprinter body metal)

--dick

surlyoldbill
02-24-2013, 05:30 AM
I was picturing the test with the plug still in the engine (why not?)

Therefore plug tip to engine head.

You could also test from the glow plug module connector to the glow plug tips, too... in case one of the wires had broken.

It wouldn't hurt to check the engine's ground strap, too. (resistance from engine to Sprinter body metal)

--dick

by plug tip, you mean the connector? It would be awful hard to reach the plug tip while it's still in the motor...:laughing:

Andyandyandy
02-24-2013, 02:07 PM
Dick, thanks for the testing info. It occurred to me last night that the problem could be as little as loose or corroded wiring connections, so I'll check that out soon. Most likely I'll end up replacing the plugs in the spring though, along with modifying the controller. It's too cold to deal with that stuff now and as I said I'm having no trouble starting.

Andy

ECU
02-24-2013, 05:15 PM
I had the light coming on from glow plugs. It would happen when the engine was cold, on short trips. It would come on with the next start. So your description would be Normal in my book.