no oil pressure at start-up intermittenly

[mbmax]

i have a 02 dmax which has displayed no oil pressure on the gauge at start-up only . The check oil pressure light goes on and i turned the truck off. No noises, started up again and everthing is normal. The dealership changed the sending unit about a year ago for exact same problem and everything was fine till now. Oil pressure is normal when driving otherwise. It has happened 4 times maybe all told and is a little unerving to say the least!Truck only has 110000 km. The dealership is looking at it on Monday and tech wants to check pin connection for sending unit. When it happens gauge shows no movement at all. I would appreciate any suggestions. Thanking you in advance

[madmatt]

put a mechanical gauge in it and see if the dash gauge reading matches. If it matches, you have a pressure problem, if not,,,electrical.

[mbmax]

Thanks madmatt for your reply. Good suggestion. The truck goes in tomorrow and i will see what the tech comes up with. He is very good to deal with and also open to opinions. I'm leaning on the side of it being an electrical issue because it just doesn't make sense to me for a pump to have no pressure then on immediate restart to build full pressure and never be low on pressure till the next time it goes to zero. However I am not an expert and appreciate your words of wisdom.

[madmatt]

Any other gauges do anything funny while the press guage is malfunctioning??? Sounds like it may just be "logic lock". I'd make sure they check for TSB's and and software updates.

[mbmax]

As best I can remember all other gauges are normal. I will ask about updates in software. He did find a TSB from last November I believe, but that nature of problems described in the bulletin didn't really fit my issue exactly and it covered a lot of years of truck. That's where he got the idea to look at the pin connection in this connector. It's the wire for the sending unit i believe. When looking at the schematics it appears the ECM is not involved,however he told me the message center monitors the gauges and lights up if a particular gauge is abnormal. Ther must be some logic involved maybe on the instrument panel but i haven't checked with him on this yet.