Next easiest step

Paul is always asking, "What's the next easiest step?" What's your next move that'll tell you the most information in the least amount of time. Up for some armchair diagnostics? I'll give you a vehicle, a complaint, and some data, and you tell me what the next easiest step is. No right or wrong answers, of course, just putting this up for discussion.

2005 Chevrolet Avalanche comes in with a complaint of the oil pressure gauge stuck high. Key on engine off.... Yep! Running is the same way. I start with a quick code scan:



Not much help there. For those unfamiliar with this truck/engine, it uses a genuine pressure transducer for the engine oil pressure. No idiot light/gauge, the gauge (usually) reflects actual oil pressure. Here's the circuit, for reference:



I start at the Instrument Cluster, wondering about a possible gauge problem. This is the data I found, KOEO:



These are converted values, transmitted from the ECM to the Cluster. To find the real sensor voltage, you have to ask the ECM. Still KOEO:



So, you've got the data, what's your next easiest step and why? Again, no right or wrong answers, just interested to see how everyone would chase this one.

I check to see if there is a gauge sweep test and see if the needle moves in the full range.

Cool concept, I like the idea!
Are those two data PID captures the same one? They've got the same number of frames and the curser is in the same place (I think it is, dealing with flash burn today)

Any who...
The Verus is already hooked up and I don't want to open the hood yet, or start taking the dash apart. So my next step is a bidirectional gauge sweep.

the verus is hooked up to it and it freezes and it takes 10 minutes to restart it.... by the time the verus gen 1 fires up id have the connector unplugged and jump the signal wire to 5 volt ref and low ref... jk noah

Noah wrote: Are those two data PID captures the same one?

:lol: Yes, yes they are. Such a professional operation... Fixed!

Any who...
The Verus is already hooked up and I don't want to open the hood yet, or start taking the dash apart. So my next step is a bidirectional gauge sweep.

Ro-longo wrote: I check to see if there is a gauge sweep test and see if the needle moves in the full range.

Great minds! I did the same, this is the scan data while sweeping back and forth:



I'll give everyone a chance to answer before going forward.

Don't know if this is your problem or not, but I have seen a few GM vehicles around this year that have problems with one or more of the gauges having problems. This is caused by the stepper motors that operate the hands of the gauges going haywire. Sometimes they will even go around too far and seem to get stuck. If this is the case you may be able to coax the needle back into position using a powerful magnet such as out of a subwoofer. Just make circular motions and the needle may get unstuck. If worse comes to worse, there are people that can repair your cluster by replacing all the stepper motors (which happen to all be the same motor).

cheryl hartkorn wrote: the verus is hooked up to it and it freezes and it takes 10 minutes to restart it....

LOL, yeah, you're not wrong!

Tyler wrote:

Noah wrote: Are those two data PID captures the same one?

:lol: Yes, yes they are. Such a professional operation... Fixed!

Any who...
The Verus is already hooked up and I don't want to open the hood yet, or start taking the dash apart. So my next step is a bidirectional gauge sweep.

Ro-longo wrote: I check to see if there is a gauge sweep test and see if the needle moves in the full range.

Great minds! I did the same, this is the scan data while sweeping back and forth:

I'll give everyone a chance to answer before going forward.

But did the gauge move?

I knew the professionals on this forum would have this one beat quickly. :lol: So I ended up following the same line of thought as everyone that replied. First the gauge sweep, 'cause I'm already hooked up to the IPC. The gauge DOES sweep, so no problem there.

The 100+ PSI pressure reading with the engine off screams skewed sensor to me, so I go for the quick unplug-it test.



Yup! I like what I'm seeing. One new oil pressure sensor later, and things are back to normal.



Is this format something we should keep doing? I think these kind of 'What would you do?' situations are a good time, especially with how important diagnostic direction is. I'll try to choose something a bit more challenging next time. :lol:

I think it's a cool format that will boost participation.
I'm excited to see how other scenarios play out.

I like this kind of stuff. Keeps the brain sharp. And get to see what others would do.

Ro-longo wrote: I like this kind of stuff. Keeps the brain sharp. And get to see what others would do.

Sweet avatar man! :woohoo:

I agree with you, it's fine and good to read a case study in a magazine, but it lacks the involvement and collective learning that something like this can provide.

Ro-longo wrote: I like this kind of stuff. Keeps the brain sharp. And get to see what others would do.

Thanks, sir!

For the record, this format isn't exclusive to me! Anyone is welcome to post up similar stuff, just keep it fun and interesting.

Brings to attention we attack problems from different ends based on personal experience with different vehicle types and the diagnostic equipment we have available. My gut reaction was start attacking the problem from the sensor end by creating a false signal.

Noah wrote: Sweet avatar man! :woohoo:

Thanks!!! If you follow scannerdanner on facebook you would have seen it there also. I made it to go along with this.

That's awesome!
I don't Facebook though