I am completely stumped-IPC OUT
Thread Starter
Drifting
Joined: Nov 2011
Posts: 1,401
Likes: 141
From: Summerville South Carolina
Thanks, Bill
sunchaser73 is 100% correct. That bare wire has NOTHING to do with your issue.
Brother,,,,,, You need a meter really bad.
With a DC Volt meter, read the following:
1. Battery voltage directly on the battery terminals engine running. If you want to read the same while you are driving down the road, measure the output of the Cigar lighter or the hot at all times AUX wire in the passengers foot well.
Battery voltage feeds the HOT AT ALL TIMES buss in each fuse box>
Both fuse boxes have a B+ stud. The battery RED positive has TWO wires. One goes to the starter and the other goes to the B+ stud on the fuse box in the engine compartment.
You will find TWO wires on the stud. The other wire feeds the passengers fuse box.
What ever battery voltage is RUNNING OR ENGINE OFF, you should read that voltage on the B+ fuse block feed.
2. Hot in ON and START or HOT in ON and RUN comes from the IGNITION SWITCH. It feeds all the modules that have dual power supplies. BCM, PCM, IPC, DCM SCM ect
These are the feeds off the ignition switch. This is from a 99 C5:
In you C5, The IPC is powered by TWO fuses from the I/P Fuse Box Fuse# 19 is the IGNITION SWITCH powered fuse and Fuse# 25 is the HOT at ALL times fuse.
On top of EACH fuse are two slots. Those are TEST points that you can read with a meter. Read fuse 19 to chassis ground when the issue happens. As long as the ignition switch is ON, you should read full BATTERY VOLTAGE on that fuse. If it is a lot lower or absent, that is a problem.
3. Serial data buss. If you pop the top off the the STAR Connector that has FOUR wires in it, you ISOLATE the LDCM, RDCM, and the Seat Module from the rest of the serial data wires.
Those three modules are or can be the cause of corrupt data on the serial data buss. Remove the shorting buss from that connector and see if the issue still happens. Post results. Yes you can drive the car with that disconnected.
4. Ignition switch HOT in ON and START feeds.
That switch gets its power from the HOT at ALL TIMES buss. Look carefully at the two connectors that the ignition switch connects to. Look for bent pins, corroded pins, melted pin sockets, There are some bent female pins in this ignition switch connector that caused a low voltage issue:
Test that stuff and see what you find.
Bill
Brother,,,,,, You need a meter really bad.
With a DC Volt meter, read the following:
1. Battery voltage directly on the battery terminals engine running. If you want to read the same while you are driving down the road, measure the output of the Cigar lighter or the hot at all times AUX wire in the passengers foot well.
Battery voltage feeds the HOT AT ALL TIMES buss in each fuse box>
Both fuse boxes have a B+ stud. The battery RED positive has TWO wires. One goes to the starter and the other goes to the B+ stud on the fuse box in the engine compartment.
You will find TWO wires on the stud. The other wire feeds the passengers fuse box.
What ever battery voltage is RUNNING OR ENGINE OFF, you should read that voltage on the B+ fuse block feed.
2. Hot in ON and START or HOT in ON and RUN comes from the IGNITION SWITCH. It feeds all the modules that have dual power supplies. BCM, PCM, IPC, DCM SCM ect
These are the feeds off the ignition switch. This is from a 99 C5:
In you C5, The IPC is powered by TWO fuses from the I/P Fuse Box Fuse# 19 is the IGNITION SWITCH powered fuse and Fuse# 25 is the HOT at ALL times fuse.
On top of EACH fuse are two slots. Those are TEST points that you can read with a meter. Read fuse 19 to chassis ground when the issue happens. As long as the ignition switch is ON, you should read full BATTERY VOLTAGE on that fuse. If it is a lot lower or absent, that is a problem.
3. Serial data buss. If you pop the top off the the STAR Connector that has FOUR wires in it, you ISOLATE the LDCM, RDCM, and the Seat Module from the rest of the serial data wires.
Those three modules are or can be the cause of corrupt data on the serial data buss. Remove the shorting buss from that connector and see if the issue still happens. Post results. Yes you can drive the car with that disconnected.
4. Ignition switch HOT in ON and START feeds.
That switch gets its power from the HOT at ALL TIMES buss. Look carefully at the two connectors that the ignition switch connects to. Look for bent pins, corroded pins, melted pin sockets, There are some bent female pins in this ignition switch connector that caused a low voltage issue:
Test that stuff and see what you find.
Bill
Except for you folks, I am on my own, as locals are clueless.
I am really grateful for all the responses and will begin to track it down
Actually, I am learning a lot and it is empowering and fun.
Dave
Thread Starter
Drifting
Joined: Nov 2011
Posts: 1,401
Likes: 141
From: Summerville South Carolina
Let me give back a little........
Dadaroo directed me to an excellent video on the site of compliance parts at EBAY. It was for installing the LMC5 Module at the BCM. It illustrates removing plugs from the BCM, removing wires from the plugs, wiring into them, etc. etc.
It is a good view for us very novice, low on theory and skills, want to be electrical DIY ers.
It is a good view for us very novice, low on theory and skills, want to be electrical DIY ers.
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
FYI, at least the tach and speedo do not get their data over the serial bus. If the serial bus was cutting out they would still work. Your info saying the voltmeter starts reading a rather low voltage and drops as it runs is a big red flag. You should read 14V if the car is just sitting there idling. I completely agree with the others to take a more careful look at the power sources for the cluster.
Since you're already talking to Dadaroo work through what he suggests and post up what you find.
Since you're already talking to Dadaroo work through what he suggests and post up what you find.
Last edited by lionelhutz; Nov 9, 2013 at 12:37 PM.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
I am going to work with David one on one with this and we have talked a lot on the phone. He does have an alternator decoupler so some drop in voltage at idle does not surprise me. We will solve this one. We will let you know how it goes. This will/has brought me up to speed significantly on serial bus design and function. I will meet with him if some initial checks and tests don't find the problem. Keep any additional input coming from any one with experience. We will NOT overlook all the input provided thus far. Mr. Sam
Thread Starter
Drifting
Joined: Nov 2011
Posts: 1,401
Likes: 141
From: Summerville South Carolina
See Sam.s post on decoupler
FYI, at least the tach and speedo do not get their data over the serial bus. If the serial bus was cutting out they would still work. Your info saying the voltmeter starts reading a rather low voltage and drops as it runs is a big red flag. You should read 14V if the car is just sitting there idling. I completely agree with the others to take a more careful look at the power sources for the cluster.
Since you're already talking to Dadaroo work through what he suggests and post up what you find.
Since you're already talking to Dadaroo work through what he suggests and post up what you find.
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
My understanding is that alternator decoupler in use has a torsional spring and 1-way clutch. It doesn't decouple the alternator at idle and the car should still be charging.
http://www.decouplerpulley.com/files/RotoRxbrochure.pdf
Look at the IDP description on page 4 and the "what to look for" text on page 5.
I think your conclusion that the decoupler pulley is causing your low idle voltage may be wrong. If it is correct, then the pulley is slipping.
http://www.decouplerpulley.com/files/RotoRxbrochure.pdf
Look at the IDP description on page 4 and the "what to look for" text on page 5.
I think your conclusion that the decoupler pulley is causing your low idle voltage may be wrong. If it is correct, then the pulley is slipping.
Last edited by lionelhutz; Nov 9, 2013 at 09:50 PM.
Melting Slicks
Joined: Nov 2009
Posts: 2,922
Likes: 219
From: West Branch, MI
David, just wanted to give you some props on your determination to get to the bottom of this problem. My kind of guy. You've got some really good folks helping you on this issue and I have no doubt you're going to find the solution soon. Good luck sir! 
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
My understanding is that alternator decoupler in use has a torsional spring and 1-way clutch. It doesn't decouple the alternator at idle and the car should still be charging.
http://www.decouplerpulley.com/files/RotoRxbrochure.pdf
Look at the IDP description on page 4 and the "what to look for" text on page 5.
I think your conclusion that the decoupler pulley is causing your low idle voltage may be wrong. If it is correct, then the pulley is slipping.
http://www.decouplerpulley.com/files/RotoRxbrochure.pdf
Look at the IDP description on page 4 and the "what to look for" text on page 5.
I think your conclusion that the decoupler pulley is causing your low idle voltage may be wrong. If it is correct, then the pulley is slipping.
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Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
My understanding is that alternator decoupler in use has a torsional spring and 1-way clutch. It doesn't decouple the alternator at idle and the car should still be charging.
http://www.decouplerpulley.com/files/RotoRxbrochure.pdf
Look at the IDP description on page 4 and the "what to look for" text on page 5.
I think your conclusion that the decoupler pulley is causing your low idle voltage may be wrong. If it is correct, then the pulley is slipping.
http://www.decouplerpulley.com/files/RotoRxbrochure.pdf
Look at the IDP description on page 4 and the "what to look for" text on page 5.
I think your conclusion that the decoupler pulley is causing your low idle voltage may be wrong. If it is correct, then the pulley is slipping.
Bill
Thread Starter
Drifting
Joined: Nov 2011
Posts: 1,401
Likes: 141
From: Summerville South Carolina
BCM middle plug wiring diagram
Bill, I need diagram showing where the black/white wire should be inserted into that plug. When I pulled that plug, that wire came out from God knows which hole. Now I have 2723 Pass Key code and car wont start. Thinking that may be the wire for it .
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
David
Which connector???? The one that comes off the Sensor on the end of the Ignition switch?
How many wires on the connector. Take a picture of it if you can.
Bill
Which connector???? The one that comes off the Sensor on the end of the Ignition switch?
How many wires on the connector. Take a picture of it if you can.
Bill
Thread Starter
Drifting
Joined: Nov 2011
Posts: 1,401
Likes: 141
From: Summerville South Carolina
Thanks for the quick
Still working to find the IPC going in and out problem. Wondering more and more if it is the BCM. Still need to do a number of voltage and continuity checks and look at ignition plugs and IPC plugs.
Thread Starter
Drifting
Joined: Nov 2011
Posts: 1,401
Likes: 141
From: Summerville South Carolina
Sam, now big problems
Hooked up PASSKey wire in right bay on BCM plug.Plugged BCM in and reconnected battery,. Now, won't start, and messages like, reduced engine power, service engine soon, Check tire pressure, service tire monitor, low fuel, service traction , etc. You name it.. Have trouble getting to code reader.
Sam is off line for awhile. Anyone?
Sam is off line for awhile. Anyone?
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Thats normally a sign of a corrupted serial data line.
Pop the top off the STAR bus connector with FOUR WIRES and see if the issue goes away.
Bill
Pop the top off the STAR bus connector with FOUR WIRES and see if the issue goes away.
Bill
Thread Starter
Drifting
Joined: Nov 2011
Posts: 1,401
Likes: 141
From: Summerville South Carolina
When I went to do that
Other than disconnecting the batt ground, I did not touch any major grounds or hots.
Going to go get a battery charger.
Last edited by David Shiel; Nov 11, 2013 at 12:56 PM.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Read the battery output directly on the battery terminals with a volt meter and see what it reads. Should be no less than 12 VDC
Have someone attempt to chank the engine and see what that voltage does.
BC
Have someone attempt to chank the engine and see what that voltage does.
BC
Thread Starter
Drifting
Joined: Nov 2011
Posts: 1,401
Likes: 141
From: Summerville South Carolina
Did that
Car won't crank. 11.9 volts at battery. No response to key, IPC, windows, radio all out. Did hear module in rear of car click for about 15 seconds. DC d the battery ground and have batt on charger now. Keeps getting more sx.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Are the battery terminals properly TORQUED to the battery??? 11 ft/lbs
Can you move any of the battery cables on the battery by hand??? If so, thats your issue.
BC
Can you move any of the battery cables on the battery by hand??? If so, thats your issue.
BC
Last edited by Bill Curlee; Nov 11, 2013 at 02:50 PM.