'94 Battery Drain - Chasing my tail
Thread Starter
6th Gear
Joined: Apr 2013
Posts: 6
Likes: 0
'94 Battery Drain - Chasing my tail
Chasing a battery drain issue on a 94. Disconnected negative battery cable, I pulled the courtesy fuses, disconnected hood lights, closed the doors, hooked up my multi-meter, and got a 400-500mA draw reading. Pulled fuses one by one. When I got to the CCM2 fuse, it dropped to 16mA. Can't imagine that being normal... I thought it may be the radio, it's aftermarket and wife tells me it powers off then back on randomly during a drive. I have confirmed this, it just restarts without reason. I removed the radio and still getting a .424mA draw with everything off.... Any other suggestions?
The battery (less than a year old) doesn't make it a week before it will no longer start the car...
The battery (less than a year old) doesn't make it a week before it will no longer start the car...
Instructor
Joined: Apr 2022
Posts: 142
Likes: 48
From: Central NY State
I have been chasing a similar battery draw on my '93. I have my courtesy switches on the doors failing, that's one cause. Linked to that is my amps on my speakers going bad. I still have to test a bunch of other things. There is a fuse tester that harbor freight makes that plugs into the fuse slots.....a little easier than multimeter on battery and pulling fuses. In the meantime, I bought a negative battery cable kill switch. That way I can still enjoy the car. When I shut the car off I pop the hood and hit the kill switch. 10 second inconvenience. Good luck.
Thread Starter
6th Gear
Joined: Apr 2013
Posts: 6
Likes: 0
CCM 2 is the battery supply to the CCM. The .424mA draw indicates that it was still "awake" when you tested. Section 8D in Book 1 explains the wake-up inputs, and conditions under which the CCM goes "asleep".
Some inputs that may be affecting your testing:
PKE Fob within range.
Key is in ignition (Stays awake for 30 minutes).
A ~.500mA draw will discharge a healthy battery in about 4-5 days. The CCM draw is most likely the cause. The cause of the draw is that the CCM is not going into idle mode. Something is keeping it "awake". Understanding the CCM strategies takes some time studying an FSM. But in the meantime, I'd re-test your draw being sure the PKE fobs are out of range, and that the key is not in the ignition. And wait at least a couple of minutes for the CCM to hibernate before accepting the reading. I'd also leave the meter set up for an overnight test. If the reading remains at .424 overnight (it probably will; because the battery eventually goes dead), yes, there's something keeping the CCM awake. I'd suspect the PKE system.
Some inputs that may be affecting your testing:
PKE Fob within range.
Key is in ignition (Stays awake for 30 minutes).
A ~.500mA draw will discharge a healthy battery in about 4-5 days. The CCM draw is most likely the cause. The cause of the draw is that the CCM is not going into idle mode. Something is keeping it "awake". Understanding the CCM strategies takes some time studying an FSM. But in the meantime, I'd re-test your draw being sure the PKE fobs are out of range, and that the key is not in the ignition. And wait at least a couple of minutes for the CCM to hibernate before accepting the reading. I'd also leave the meter set up for an overnight test. If the reading remains at .424 overnight (it probably will; because the battery eventually goes dead), yes, there's something keeping the CCM awake. I'd suspect the PKE system.
I don't have any FOB's because the previous owner lost them. But I will try again with the key out for a while and report back.
Thanks again!
Thread Starter
6th Gear
Joined: Apr 2013
Posts: 6
Likes: 0
CCM 2 is the battery supply to the CCM. The .424mA draw indicates that it was still "awake" when you tested. Section 8D in Book 1 explains the wake-up inputs, and conditions under which the CCM goes "asleep".
Some inputs that may be affecting your testing:
PKE Fob within range.
Key is in ignition (Stays awake for 30 minutes).
A ~.500mA draw will discharge a healthy battery in about 4-5 days. The CCM draw is most likely the cause. The cause of the draw is that the CCM is not going into idle mode. Something is keeping it "awake". Understanding the CCM strategies takes some time studying an FSM. But in the meantime, I'd re-test your draw being sure the PKE fobs are out of range, and that the key is not in the ignition. And wait at least a couple of minutes for the CCM to hibernate before accepting the reading. I'd also leave the meter set up for an overnight test. If the reading remains at .424 overnight (it probably will; because the battery eventually goes dead), yes, there's something keeping the CCM awake. I'd suspect the PKE system.
Some inputs that may be affecting your testing:
PKE Fob within range.
Key is in ignition (Stays awake for 30 minutes).
A ~.500mA draw will discharge a healthy battery in about 4-5 days. The CCM draw is most likely the cause. The cause of the draw is that the CCM is not going into idle mode. Something is keeping it "awake". Understanding the CCM strategies takes some time studying an FSM. But in the meantime, I'd re-test your draw being sure the PKE fobs are out of range, and that the key is not in the ignition. And wait at least a couple of minutes for the CCM to hibernate before accepting the reading. I'd also leave the meter set up for an overnight test. If the reading remains at .424 overnight (it probably will; because the battery eventually goes dead), yes, there's something keeping the CCM awake. I'd suspect the PKE system.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
I understand the problem and made those measurements myself. I have watched the current go down to 30 ma as the lights go off and the CCM goes to idle.
Somewhere I read if the key locks were not in the vertical position it can cause a problem. I just can't remember the exact conditions. But I would rock the key locks and then go to the vertical position just to make sure.
Want to check to door light plungers for adjustment and that the lights are out in the center console and under the hood.
In regard to the PKE comment, you can always pull the fuses for it in case it is active.
Somewhere I read if the key locks were not in the vertical position it can cause a problem. I just can't remember the exact conditions. But I would rock the key locks and then go to the vertical position just to make sure.
Want to check to door light plungers for adjustment and that the lights are out in the center console and under the hood.
In regard to the PKE comment, you can always pull the fuses for it in case it is active.
Thread Starter
6th Gear
Joined: Apr 2013
Posts: 6
Likes: 0
I understand the problem and made those measurements myself. I have watched the current go down to 30 ma as the lights go off and the CCM goes to idle.
Somewhere I read if the key locks were not in the vertical position it can cause a problem. I just can't remember the exact conditions. But I would rock the key locks and then go to the vertical position just to make sure.
Want to check to door light plungers for adjustment and that the lights are out in the center console and under the hood.
In regard to the PKE comment, you can always pull the fuses for it in case it is active.
Somewhere I read if the key locks were not in the vertical position it can cause a problem. I just can't remember the exact conditions. But I would rock the key locks and then go to the vertical position just to make sure.
Want to check to door light plungers for adjustment and that the lights are out in the center console and under the hood.
In regard to the PKE comment, you can always pull the fuses for it in case it is active.
Will pulling the PKE fuses mess with anything else? Car will still function fine?
Instructor
Joined: Sep 2004
Posts: 139
Likes: 3
From: Rockland County NY
I thought I hit the jackpot when I read the first post so I was disappointed to see the thread end.
I have the dash still off from replacing the heater core last month and while open I fixed the chime module (see my other posts/threads if interested). I was going to replace the PKE that I turned off 10 years ago because the alarm started going off for no reason and when the rear hatch opened while driving, I had enough. So now that everything is open, it was time for the PKE.
But something happened during my break from working on the car (it was running just a few days before) and I came back to a totally dead battery. When I hooked it up to the charger after it got a bit of juice, when I opened the car door, I heard a clicking noise. I didn't know what that was at the time but now a few days later, battery charged up and I got a multimeter with a higher DC amp range than my little one, I hooked it up inline to the battery and saw it was draining about 300+ mA. Strangely the courtesy lights did not turn on (did CCM read too little voltage to turn them on?) but the clicking noise was back. I started pullling fuses and after pulling the CCM2, it dropped to 25ma.
So now what?
I have the dash still off from replacing the heater core last month and while open I fixed the chime module (see my other posts/threads if interested). I was going to replace the PKE that I turned off 10 years ago because the alarm started going off for no reason and when the rear hatch opened while driving, I had enough. So now that everything is open, it was time for the PKE.
But something happened during my break from working on the car (it was running just a few days before) and I came back to a totally dead battery. When I hooked it up to the charger after it got a bit of juice, when I opened the car door, I heard a clicking noise. I didn't know what that was at the time but now a few days later, battery charged up and I got a multimeter with a higher DC amp range than my little one, I hooked it up inline to the battery and saw it was draining about 300+ mA. Strangely the courtesy lights did not turn on (did CCM read too little voltage to turn them on?) but the clicking noise was back. I started pullling fuses and after pulling the CCM2, it dropped to 25ma.
So now what?
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