Trip Computer Resets

[bpage]

I recently purchased a 1997 Eldorado with 77000 miles on it. Everything seems to work properly except the trip computer. After the ignition has been off for approximately 19 minutes everything on the trip computer resets back to zero ( trip odometer, avg mpg, fuel used, etc.). The radio also resets itself to FM 98.1. The presets on the radio are not affected. The RKE still works as it should although the button sometimes needs to be pushed 3 or 4 times to unlock the doors. Has anyone heard of this problem? What should I do to get it working properly.

[BodybyFisher]

First check for codes to see if any have been set, do you know how to check them?

Then check your battery terminals to make sure they are clean and tight especially the positive cable and have the battery load tested

[Texas Jim]

I am not understanding something....

You state............After the ignition has been off for approximately 19 minutes..........everything resets...

If the ignition if "OFF".... how can you tell when it resets ???

I am confused....

[bpage]

Sorry about the confusion. When I turn the ignition back on after it has been off for approximately 19 minutes the reset has occured. After 18 minutes everything is still the same as it was when turned off.

[bpage]

First check for codes to see if any have been set, do you know how to check them?

Then check your battery terminals to make sure they are clean and tight especially the positive cable and have the battery load tested

[bpage]

I don't know how to check codes using the driver information center. I do have an OBDII code checker but I haven't used it yet. There seems to be a lot of problems caused by poor battery terminal connections posted on the Forum. I haven't cleaned the battery terminals. The battery is a 4 year old DIEHARD GOLD and the terminals look like new. The car has been garaged for past 4 years with only about 6000 miles since the battery was replaced.

The battery voltage is 12v with ignition on and 13.4v with engine running.

[Texas Jim]

To read the codes go to the home page...click on the HOW TO section and then go down to the section where it tells you how to read codes.

The 19 minute thing is puzzling... to say the least.

These cars are real sensitive to bad connections.

Take the terminals off and on the red one.... pull back the red rubber covering and you will see that there is more than one connection there.

Clean each connection and then reassemble the terminals and reconnect to battery.

[bpage]

To read the codes go to the home page...click on the HOW TO section and then go down to the section where it tells you how to read codes.

The 19 minute thing is puzzling... to say the least.

These cars are real sensitive to bad connections.

Take the terminals off and on the red one.... pull back the red rubber covering and you will see that there is more than one connection there.

Clean each connection and then reassemble the terminals and reconnect to battery.

[bpage]

Thanks Texas Jim. I'll try this as soon as I get some free time and it's not 95 degrees out. It seems that cleaning battery terminals is a quick fix for a lot of weird electrical problems on Cadillacs. I lived in Granbury Texas back in the late 80's. Fort Worth Rocks.

[cdgrinci]

I don't know the connection, but the 19 minutes is just about the amount of time that the accessories are timed to remain on after ignition is turned off (as long as you don't exit the vehicle); maybe something in the electronic control for that. My statement is a total WAG, but maybe a connection.

[BodybyFisher]

I don't know the connection, but the 19 minutes is just about the amount of time that the accessories are timed to remain on after ignition is turned off (as long as you don't exit the vehicle); maybe something in the electronic control for that. My statement is a total WAG, but maybe a connection.

I thought about what you were saying also, that is was related to the retained accessory power circuits but I believe that is a 10 minute timer. But the retained accessory power circuit (not sure if that is the official name but that is what I call it), does not affect volitile memory, it shuts off the radio, windows, etc.

Things that cause volitile memory reset are a loss or disconnection of power. The odd thing here is why it happens at 19 minutes, but I think that is just a coincidence. Keep in mind that this member said he CHECKED it at 18 minutes, IF he checked it at 18 min, the retained power circuits would have reset themselves unless the door was open, so no way the RAP would shut off in ONE minute then.

I think a good and I mean GOOD cleaning of the battery connections with taking the positive cable apart and a battery test must be done to eliminate that possibility.

Then main breakers and fuses should be checked for green/white corrosion

Codes could be setting that may give a hint to what is going on

[BodybyFisher]

One more thing does this car START everytime with no click, black out or flicker?

[bpage]

I don't know the connection, but the 19 minutes is just about the amount of time that the accessories are timed to remain on after ignition is turned off (as long as you don't exit the vehicle); maybe something in the electronic control for that. My statement is a total WAG, but maybe a connection.

I thought about what you were saying also, that is was related to the retained accessory power circuits but I believe that is a 10 minute timer. But the retained accessory power circuit (not sure if that is the official name but that is what I call it), does not affect volitile memory, it shuts off the radio, windows, etc.

Things that cause volitile memory reset are a loss or disconnection of power. The odd thing here is why it happens at 19 minutes, but I think that is just a coincidence. Keep in mind that this member said he CHECKED it at 18 minutes, IF he checked it at 18 min, the retained power circuits would have reset themselves unless the door was open, so no way the RAP would shut off in ONE minute then.

I think a good and I mean GOOD cleaning of the battery connections with taking the positive cable apart and a battery test must be done to eliminate that possibility.

Then main breakers and fuses should be checked for green/white corrosion

Codes could be setting that may give a hint to what is going on

[bpage]

Everybody seems to think the battery is the place to start trouble shooting, so that's what I will do this weekend. I'll be back with a full report! Thanks for the advice.

[bpage]

One more thing does this car START everytime with no click, black out or flicker?

[bpage]

I'm not sure what click black or flicker is but I have noticed nothing unusual when I start the car.

[bpage]

I had a chsnce to check for diagnostic codes today. The following codes are set in HISTORY. B1552, B1771, B2560, P0603, U1255.

I will try cleaning battery cables tomorrow. Any idea where to go from here?

[Texas Jim]

B1552 - Keep Alive Memory (KAM) Error

B2560 - Remote Keyless Entry Message Validation Error

P0603 - Control Module Long Term Memory Reset

U1255 - Serial Data Line Malfunction

I did not find a code B1771.... I did find code

B1171 - Internal SDM Failure

The first 4 look like they could all relate to a bad or loose battery cable or a weak battery.

The last one.. I don't know...

[BodybyFisher]

B1552 - Keep Alive Memory (KAM) Error HAVE YOU DISCONNECTED THE BATTERY LATELY? YES OR NO?

B1771 - Cassette tape slow

B2560 - RKE Message Validation Error

P0603 - Control Module Long Term Memory Reset HAVE YOU DISCONNECTED THE BATTERY LATELY? YES OR NO?

P0603 - Control Module Long Term Memory Reset

Circuit Description

The PCM has a memory area where it stores certain data it needs to save when the key is turned OFF. This area is called Keep Alive Memory. This diagnostic test monitors the PCM's keep alive memory for a loss or unintended change of data. If such a condition occurs, DTC P0603 will set.

Conditions for Setting the DTC

Test Condition

Test continuously.

Failure Condition

Keep alive memory checksum does not match previous checksum.

Action Taken When the DTC Sets

Clear all keep alive memory locations.

The Malfunction Indicator Lamp (MIL) will not illuminate.

No message will be displayed.

Conditions for Clearing the DTC

A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test.

A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.

Use a scan tool to clear DTCs.

Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended.

Diagnostic Aids

If the battery has been disconnected for any reason DTC P0603 will set. The PCM keeps a running check on the memory; if memory changes it resets. An intermittent loss of power or ground to the PCM will cause a reset

[BodybyFisher]

Check battery connections, battery condition, breaker/fuses for corrosion

[bpage]

I don't know the connection, but the 19 minutes is just about the amount of time that the accessories are timed to remain on after ignition is turned off (as long as you don't exit the vehicle); maybe something in the electronic control for that. My statement is a total WAG, but maybe a connection.

I thought about what you were saying also, that is was related to the retained accessory power circuits but I believe that is a 10 minute timer. But the retained accessory power circuit (not sure if that is the official name but that is what I call it), does not affect volitile memory, it shuts off the radio, windows, etc.

Things that cause volitile memory reset are a loss or disconnection of power. The odd thing here is why it happens at 19 minutes, but I think that is just a coincidence. Keep in mind that this member said he CHECKED it at 18 minutes, IF he checked it at 18 min, the retained power circuits would have reset themselves unless the door was open, so no way the RAP would shut off in ONE minute then.

I think a good and I mean GOOD cleaning of the battery connections with taking the positive cable apart and a battery test must be done to eliminate that possibility.

Then main breakers and fuses should be checked for green/white corrosion

Codes could be setting that may give a hint to what is going on

[bpage]

I gave the battery cables a GOOD cleaning this weekend. The cables looked clean, no corosion at all, although both cables seemed a little loose. The problem is still the same. Some replys suggest checking for bad grounds. I don't know where to start on this. Are there any likely spots? One post said that the data buss for the body control module goes through the radio and that replacing the radio solved a similar problem. How likely is this? I have the atandard non BOSE cassette radio. I would like to replace the radio with the optional cassette/CD radio if I can find one. What kind of headaches might this cause.

[BodybyFisher]

Interesting problem

Are you sure that it appears that the system 'resets' at about 18 to 19 minutes?, can you replicate that over and over?

Do you have an ohm meter?

Did this just begin happening? Tell us the history of this car and problem. Did you acquire this car with the problem or did this just start happening?

[bpage]

I am thinking the same as you. I checked the reset timing about 10 times at different time intervals to see if it was random or if it happened at the same time each time the ignition was turned off. It is OK after 18 minutes but not after 19 minutes. If I wanted to fool with it for half a day I bet I could narrow it down to minutes and seconds. It's almost like it's on a timer. It must be some sort of computer thing otherwise I think the timing would vary. I did notice one other thing last night after I cleaned the battery terminals. The RKE seems to be somewhat unresponsive, sometimes it takes 3 or 4 button presses before it works. Last night I had to push the trunk release about 8 times before it worked. I was checking to see if the problem came back after 19 minutes, after 3 clicks I noticed that the radio lit up on 98.1 and went off on click the door finally opened. I changed the battery in the KEYFOB 2 weeks ago.

I do have a multimeter and an Octron Scantool.

I bought the car May 27 from the original owner and the Father of a good friend. The reset problem came to my attention the next day when the radio kept resetting to 98.1. The car has always been garaged and very well maintained. It has only been in the snow a few times. From looking around the car there is not a spec of rust or corossion anywhere. The car has been sitting a lot lately, only 6000 miles in the last 4 years. If the car had been exposed to the elements more then I would suspect that a coroded ground would be more probable.

[BodybyFisher]

Explain this statement to me again in more detail:

I was checking to see if the problem came back after 19 minutes, after 3 clicks I noticed that the radio lit up on 98.1 and went off on click the door finally opened.

You were trying to open the door with the key fob and the radio cam on? Three clicks of what, the key fob? That is not standard for the radio to come on when the door is unlocked, am I getting that right, you unlocked the door and the radio came on?, and was reset?

Do you have a remote start?

Is this the original radio?

Did anyone rewire the radio?

Once I find out what is going on, Ill search the manual and schematics, this is an odd one.