Couple of Codes '99 STS

[CadiKing]

Hello Everyone,

I have some codes which have been setting under history, but not

current. (What's up with that?)

Even though I reset the codes, they return same day

under history, never Current. These two codes are as follows.

AMP U1064 - Loss of Communication with DIM

DIM B1324 - AC Refridgerent Overpressure

Two other codes seem to keep coming back, however,

not right away.

DDM U1255 - Class 2 communication Malfunction

Serial Data Line Malfunction

PCM P1617 - Engine oil Level Switch Circuit

I have the manuals for the car, '99 STS,

How do I diagnose the problems?

For the AC Over pressure...How do I verify and correct?

Does this have to be analyzed by a technition?

For instance Code PCM P1617 - (Engine oil Level Switch Circuit)

Does this tell me the switch needs replaced, or should

I try to find a fault in the wiring, etc.

Any guideance will be greatly appreciated! Thank you all in advance.

[KHE]

has any refrigerant been added to the system? If so, it may be overcharged. Another possibility would be a malfunctioning hi-pressure switch. You would need to have a shop check the refrigerant pressures and/or evacuate, weigh the refrigerant and recharge the proper amount back into the system.

[CadiKing]

KHE,

Thank you for the reply.

I have owned the car for 10 months and no refrigerant has been

added under my watch. The AC worked fine all summer, and even

now I do not have any problems.

Can I test the switch myself?

If not, then when I have a shop test/weigh the system,

if it is NOT overcharged, does that tell me the switch is

bad?

If it IS overcharged, replace with proper amount, (2 lbs.?),

and the code should not return. Does this sound correct?

thank you,

[PAUL T]

In your manual under each code description there should be a diagnostic flow chart to work from. This will tell you where and what to look for.

[MARK 99STS]

CadiKing,

The AMP UP1064 is an internal glich between your radio amp and the PCM. I have the same code and researched it to find it was nothing to worry about. Has something to do with the communication between the two. I can't help you with the others.

[CadiKing]

Mark 99STS,

Thanks for the headsup on that code...

I will not loose any more sleep over it...

thanks again,

[KHE]

KHE,

Thank you for the reply.

I have owned the car for 10 months and no refrigerant has been

added under my watch. The AC worked fine all summer, and even

now I do not have any problems.

Can I test the switch myself?

If not, then when I have a shop test/weigh the system,

if it is NOT overcharged, does that tell me the switch is

bad?

If it IS overcharged, replace with proper amount, (2 lbs.?),

and the code should not return. Does this sound correct?

thank you,

Since the AC code isn't current, I probably wouldn't worry about it. Try unplugging the sensor (it is on the small diameter high pressure line that runs along the firewall) and verify that the contacts are clean and then plug it back in.

[CadiKing]

KHE,

Thank you for the advice again...

I will do as you suggest.

Any reason why these codes seem to set as history.

I never have seen a code listed as current.

I see in the manual that these particular codes do not

turn on the service light.

thanks again,