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Battery being drained


Phillip

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I have a strange problem. When I shut off the car, there is a drain on the battery that eventually runs it down. The PRNDL light on the dash and shift stays on with the ignition off and I also discovered that the PCM remains on. I found out about the PCM when I plugged my Scan Tool into the OBD II port and it started communicating with the car without turning the ignition on. These are the only anomolies I have found so far. There are no codes at all.

Any suggestions are welcome.

Phillip

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First, Check for codes via the on board computer rather than the scan tool, some things show up on the on board computer and not a scan tool (unless you are talking about a TECH 2).

Second, disconnect the battery for a minute and let the system restart

Do the radio and windows work when this occurs? This could be a bad retained power circuit, just a guess.

There is also a sleep circuit, if I recall, but check codes first.

I have never done it but you can put an amp meter on your battery see the draw, and start pulling fuses, breakers and relays to see what circuit is causing this.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Good suggestions. I have already checked the codes. You are right in your post. I can view more codes with the on board diagnostics than with the scan tool. I have also disconnected the battery and reset everything. No change there.

I understand that the PZM had a retained accessory feature. So far, all the features that are controlled by it seem to be performing normally.

It looks like I may have to follow the ammeter approach. It looks time consuming and I don't have the tool J38785. Does anyone know what this is or if there is an alternative? I am clearly not to savy with the electronic stuff.

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Phil, see this thread this might help with how to diagnose and how to measure current

http://caddyinfo.ipbhost.com/index.php?sho...17&hl=amp+meter

You need to measure current. I think you can use a voltmeter set to amps and put it in line with your positive cable, but DON'T turn on the key or you will burn out your meter.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Thanks for the link to the previous thread. Some of what REK experienced sounds familiar. I wish he had posted a final note to let us know what he found.

Tomorrow I will try the voltmeter-ammeter thing to see if I can find a drain. Having the lights and PCM on should give me a head start.

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Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Set the meter to the highest current range and connect it in series with the negative battery lead. You will need to disconnect the negative battery cable, connect the positive lead of the meter to the negative battery cable and the negative lead of the meter to the negative terminal of the battery. Note the current reading and remove the fuses one by one and when you pull the one that minimizes the current drain, you've found the problem circuit.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Set the meter to the highest current range and connect it in series with the negative battery lead. You will need to disconnect the negative battery cable, connect the positive lead of the meter to the negative battery cable and the negative lead of the meter to the negative terminal of the battery. Note the current reading and remove the fuses one by one and when you pull the one that minimizes the current drain, you've found the problem circuit.

Thanks Kevin, I thought it was the positive cable so that it showed a positive drain on the meter..

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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An alternative is to use a 12 volt test lamp in place of an ammeter in series with the battery cable. Any significant current draw will light the test light.

Regards,

Warren

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There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises

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Set the meter to the highest current range and connect it in series with the negative battery lead. You will need to disconnect the negative battery cable, connect the positive lead of the meter to the negative battery cable and the negative lead of the meter to the negative terminal of the battery. Note the current reading and remove the fuses one by one and when you pull the one that minimizes the current drain, you've found the problem circuit.

Thanks Kevin, I thought it was the positive cable so that it showed a positive drain on the meter..

Either method will work - it is easier to monitor it through the negative lead as it is only one cable to disconnect. I don't like to just disconnect the positive cable as the risk of getting a lesson in welding 101 is high. :lol: If you want to use the meter in series with the positive cable, the positive lead of the meter needs to be connected to the positive terminal of the battery and the negative meter lead to the positive battery cable. The meter will show a positive reading regardless of the method due to the polarity of the connections. I'm referring to an analog meter - a digital meter will indicate the polarity regardless of the lead connections.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Set the meter to the highest current range and connect it in series with the negative battery lead. You will need to disconnect the negative battery cable, connect the positive lead of the meter to the negative battery cable and the negative lead of the meter to the negative terminal of the battery. Note the current reading and remove the fuses one by one and when you pull the one that minimizes the current drain, you've found the problem circuit.

Thanks Kevin, I thought it was the positive cable so that it showed a positive drain on the meter..

Either method will work - it is easier to monitor it through the negative lead as it is only one cable to disconnect. I don't like to just disconnect the positive cable as the risk of getting a lesson in welding 101 is high. :lol: If you want to use the meter in series with the positive cable, the positive lead of the meter needs to be connected to the positive terminal of the battery and the negative meter lead to the positive battery cable. The meter will show a positive reading regardless of the method due to the polarity of the connections. I'm referring to an analog meter - a digital meter will indicate the polarity regardless of the lead connections.

True an analog meter will just pin in the wrong direction and you would just need to swap the polarity. Very very good point about the welding lesson, that did not occur to me, although it should have! Not only that, you are right there are two cables at the positive cable making it too hard to accomplish the task. Negative it is, Thanks

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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It was a Leaking diode in the Alt. No such thing as Diode-sealer, parts to do a complete rebuild cost slightly less than a Reman Delco, so I went with a new Alt. It works fine now. I reread the old post (link/BBF), I never found out what the "Click" was from. I'm guessing it just might have been some loose "Crainial" material, coming to rest when I tilted my head...

rek

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REK,

Thanks for coming back with that. I will watch for the same problem. As for the click, I wouldn't be surprised if it was a relay clicking. When the voltage gets low, there is a relay on the drivers side under the hood that goes crazy.

Thanks for the tip on the battery cables too. Yeah, we all know about the risk of tampering with the postive terminal, however it is so easy to forget.

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Well, I went through the diagnosis outlined in the shop manual and now I am really confused. The drain on the battery, with all accessories off and the PZM sleeping, should be below 30 mA. Mine is about 3.6 A. OUCH. That'll drain the battery quick. Unfortunately I found several things contributing to the drain. The RTD fuses and COMFORT fuses in the trunk accounted for the bulk of it and the PCM fuse under the hood contibuted about .5A. With so many systems contributing to the drain, I don't know where to go next.

rek, how did you diagnose the leaking diode in the alternator?

I am going to search the archives, but I am open to suggestions.

Thanks

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Phil, something happened today to me and I thought of your problem. Very interesting. I did my RF hub bearing. I had the car jacked up and i wanted to remove the three bolts by putting my socket through the hub flange. In order to turn the hub flange, I needed to take the car out of park to be able to turn the axle. So I got into the car, put the parking brake on, and put the car in Neutral to release the tranny lock in park so i could turn the axle. I went to turn off the key.... and lo and behold, everything went off EXCEPT for the PRNDL indicator! I immediately thought about YOU! I have a feeling that your KEY switch is not turning off fully! You either have a misadjustment in your SELECTOR so that the car is NOT in park or does not appear to be in park.... Check that thought out. Someone else check my premise. Turn your key on, car off, put the car in R or N, and turn the key off as far as it goes, everything will go off EXCEPT the PRNDL indicator! Good Luck, Mike

By the way, in order to stop this from happening I disconnected the negative lead on the battery while I worked on the car, so that I didnt drain the battery with the car in R or N, and the key partially on....

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I am thinking that your manual linkage is misadjusted somehow. If the car is out of PARK, I get the same symptom you have. Put your car in park and see if its in park buy trying to push it, it might roll, so be careful.

ALso, if in fact the tranny is in park (the parking pawl is engaged), it could be in your switch area related to the locking mechanism of the steering wheel, tranny, etc. Ill look in my manual later, Mike

Logan, what do you think about this problem? What could cause the indicator to read PARK and the manual linkage NOT be in PARK. Or in the steering wheel, what could interfere with the KEY being turned to OFF, as if the Gear Selector is in something OTHER THAN PARK? THanks

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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That is a strange coincidence. I wonder if it is possible that the car thinks it should be on even after the key has been removed. I know that the PCM stays on, although I have found evidence that the PZM goes to "sleep" as it should.

I will do some more reading on this and see where it goes.

Thanks for the input and I am glad to hear that you got that bearing replaced.

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Bruce, you have done some steering wheel and steering column work. What do you think of the above problem? Considering that I get the same signs when my car is in something other than PARK when I turn the key off, what can happen in the column to create this problem? Is there a cable that locks the steering column and selector that could be broken or maladjusted? Thanks for thinking about this, Mike

PS, shouldnt this set a code also?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Well the saga continues. I drove the car today and it gave me a few codes to work with. Most of them relate to the battery being disconnected (a necessity if I want to start it after any length of time). Unfortunately, I got a couple of PZM codes that look pretty grim: PZ1558 and PZ2056. The shop manual doesn't give much hope. There is no diagnosis required for a PZ1558 code, simply replace the PZM.

I generally trust the manual, but you usually have a more thorough diagnosis to go by. I wonder if there is any chance the problem is a bad connection somewhere? I priced a body control module at Rock Auto and it was $190 for a Delco and $100 for a generic brand. Any suggestions?

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When the car is put into park, there is a PRNDL switch in the vicinity of the gear selector which signals the selection to the PCM. Perhaps the PRNDL switch needs to be replaced.

I am not clear, however, with accessory retained power, whether you should expect the light to go out on the PRNDL indicator after you remove the key but before you open the door. In my CTS the car continues to run the radio, lights, etc until the door is opened.

Bruce, you have done some steering wheel and steering column work. What do you think of the above problem? Considering that I get the same signs when my car is in something other than PARK when I turn the key off, what can happen in the column to create this problem? Is there a cable that locks the steering column and selector that could be broken or maladjusted? Thanks for thinking about this, Mike

PS, shouldnt this set a code also?

Bruce

2016 Cadillac ATS-V gray/black

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I believe you are correct with the retained power the PRNDL indicator goes out, windows, radio will continue to run. Do you know if the PRNDL switch would set a code?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Phil, something happened today to me and I thought of your problem. Very interesting. I did my RF hub bearing. I had the car jacked up and i wanted to remove the three bolts by putting my socket through the hub flange. In order to turn the hub flange, I needed to take the car out of park to be able to turn the axle. So I got into the car, put the parking brake on, and put the car in Neutral to release the tranny lock in park so i could turn the axle. I went to turn off the key.... and lo and behold, everything went off EXCEPT for the PRNDL indicator! I immediately thought about YOU! I have a feeling that your KEY switch is not turning off fully! You either have a misadjustment in your SELECTOR so that the car is NOT in park or does not appear to be in park.... Check that thought out. Someone else check my premise. Turn your key on, car off, put the car in R or N, and turn the key off as far as it goes, everything will go off EXCEPT the PRNDL indicator! Good Luck, Mike

By the way, in order to stop this from happening I disconnected the negative lead on the battery while I worked on the car, so that I didnt drain the battery with the car in R or N, and the key partially on....

Mike,

My car does not do that. When gear selector is in N, I can turn ignition OFF and everything goes OFF including PRNDL light. BTW, can you remove the key with slector in N? I had to "modify" my ignition system, but it seems that the ignition switch is blocked mechanically from moving to the initial/final position (a position you enter the key into the ignition lock ctlinder).

This is just a guess, but the ignition swith which is attached to the steering column may need adjustment (it is attached to the column with a few bolts and there is plenty of room for adjustment).

Bruce,

If you refer to PRNDL switch also known as neutral safety switch, it is on top of transmission. There is an adjustment procedure in FSM. Misadjusted PRNDL switch usually results in "no start in Park" condition.

The saddest thing in life is wasted talent

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The drain on the battery, with all accessories off and the PZM sleeping, should be below 30 mA. Mine is about 3.6 A. OUCH. That'll drain the battery quick. Unfortunately I found several things contributing to the drain. The RTD fuses and COMFORT fuses in the trunk accounted for the bulk of it and the PCM fuse under the hood contibuted about .5A.

Okay, here's one from left field: the COMFORT circuit includes the radio; any chance your power antenna is stuck?

There is *NO WAY* (absent smoke) the PCM will draw half an amp in standby. I'd guess there are other components on that fuse.

Regards,

Warren

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There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises

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According to the electrical schematics, the PRNDL in the dash is NOT on retained accessory power. Further, this afternoon when I shut the car down, the whole dash PRNDL flashed about 5 times, went off for a few seconds, then came on and flashed about 5 times. Repeated this cycle several times and then went back to just having the P lit. Very strange.

I agree with Warren that there are too many amps being drawn to be going through the PCM. In fact when I was doing the parasitic drain test, I found that the PCM was drawing about 0.7A, the COMFORT circuit was drawing about 1.5A and the RTD circuit (which feeds the Road sensing suspension) was drawing 1.2A. These account for the total draw of about 3.4A.

Even with this load on the car, aside from the lights on the two PRNDL's and the PCM, there is no evidence of any activity in the car. The stereo is silent, all the lights are off and there are no fans running.

Is it possible that the PZM could be causing all these things to be happening?

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Phil, something happened today to me and I thought of your problem. Very interesting. I did my RF hub bearing. I had the car jacked up and i wanted to remove the three bolts by putting my socket through the hub flange. In order to turn the hub flange, I needed to take the car out of park to be able to turn the axle. So I got into the car, put the parking brake on, and put the car in Neutral to release the tranny lock in park so i could turn the axle. I went to turn off the key.... and lo and behold, everything went off EXCEPT for the PRNDL indicator! I immediately thought about YOU! I have a feeling that your KEY switch is not turning off fully! You either have a misadjustment in your SELECTOR so that the car is NOT in park or does not appear to be in park.... Check that thought out. Someone else check my premise. Turn your key on, car off, put the car in R or N, and turn the key off as far as it goes, everything will go off EXCEPT the PRNDL indicator! Good Luck, Mike

By the way, in order to stop this from happening I disconnected the negative lead on the battery while I worked on the car, so that I didnt drain the battery with the car in R or N, and the key partially on....

Mike,

My car does not do that. When gear selector is in N, I can turn ignition OFF and everything goes OFF including PRNDL light. BTW, can you remove the key with slector in N? I had to "modify" my ignition system, but it seems that the ignition switch is blocked mechanically from moving to the initial/final position (a position you enter the key into the ignition lock ctlinder).

This is just a guess, but the ignition swith which is attached to the steering column may need adjustment (it is attached to the column with a few bolts and there is plenty of room for adjustment).

Bruce,

If you refer to PRNDL switch also known as neutral safety switch, it is on top of transmission. There is an adjustment procedure in FSM. Misadjusted PRNDL switch usually results in "no start in Park" condition.

Not to offend you Adallak but as much as my car is a relic, yours is a dynasaur and totally different, :lol:

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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