ALARM GOES OFF - Need help with pulled codes
Thread Starter
Drifting
Joined: Sep 2002
Posts: 1,571
Likes: 1
From: suburban Philadelphia PA
ALARM GOES OFF - Need help with pulled codes
2001 C5: Update from previous thread (2 weeks ago)
ISSUE: Factory alarm goes off when unlocking doors with keyfob(s) (with fresh batteries), once pulling on exterior door handles. Car has a fresh battery, but the alarm was causing issues before the battery swap about 1 year ago. Car is stored with Battery Tender. No electrical mods, other than Window Valet - which had been in the car for many years.
All codes were cleared ... car was locked with keyfob. 24 hours later, I unlocked doors with keyfob, attempted to open drivers door with door handle ... alarm went off.
UPDATE: The car was locked for 48 hours. During this time, the key fob was more than 50' away from the car. I would attempt to unlock the car using a key fob with a fresh battery. When I clicked the door unlock button, the door unlocks - but the dash does not light up. I tried to pop the hatch release on the key fob, but it does not work. When I open the door, the alarm goes off.
After halting the alarm, I get inside the car and close the door. I checked the codes, found:
AO-LDCM - U1064H
A1-RDCM - U1064H
A6 - SCM - U1255H
The car has not had any water inside, though the previous battery threw-up on itself (sweated / leaked battery acid from a seam). I took the car to a Chevrolet dealer, who replaced the battery, and said they neutralized the acid. Afterwards, I took the car to a Corvette specialist who noticed peeling paint underneath the car (thought he said the frame). They said some of the (vacuum?) lines under the battery started to corrode or deteriorate. The lines were replaced, peeling areas were painted where necessary, and the entire area was neutralized with what I was told was a product designed for battery acid.
Any thoughts?
ISSUE: Factory alarm goes off when unlocking doors with keyfob(s) (with fresh batteries), once pulling on exterior door handles. Car has a fresh battery, but the alarm was causing issues before the battery swap about 1 year ago. Car is stored with Battery Tender. No electrical mods, other than Window Valet - which had been in the car for many years.
All codes were cleared ... car was locked with keyfob. 24 hours later, I unlocked doors with keyfob, attempted to open drivers door with door handle ... alarm went off.
UPDATE: The car was locked for 48 hours. During this time, the key fob was more than 50' away from the car. I would attempt to unlock the car using a key fob with a fresh battery. When I clicked the door unlock button, the door unlocks - but the dash does not light up. I tried to pop the hatch release on the key fob, but it does not work. When I open the door, the alarm goes off.
After halting the alarm, I get inside the car and close the door. I checked the codes, found:
AO-LDCM - U1064H
A1-RDCM - U1064H
A6 - SCM - U1255H
The car has not had any water inside, though the previous battery threw-up on itself (sweated / leaked battery acid from a seam). I took the car to a Chevrolet dealer, who replaced the battery, and said they neutralized the acid. Afterwards, I took the car to a Corvette specialist who noticed peeling paint underneath the car (thought he said the frame). They said some of the (vacuum?) lines under the battery started to corrode or deteriorate. The lines were replaced, peeling areas were painted where necessary, and the entire area was neutralized with what I was told was a product designed for battery acid.
Any thoughts?
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
Delete those codes and see what comes back. If you turn OFF the ignition almost all codes will show as H. If you pull them before you turn the ignition OFF you have to reset any messages on the DIC first.
Thread Starter
Drifting
Joined: Sep 2002
Posts: 1,571
Likes: 1
From: suburban Philadelphia PA
Having just reviewed your thread from earlier this month and seeing that you stated you "cleared" the codes in this new thread, I have to think that you have a recurring problem with the serial data buss. The LDCM and RDCM both reported loss of communications to the BCM (U1064) and the SCM reported a general failure of the serial data buss (U12555).
I suspect the cause of this is the Seat Controller Module (SCM) that reported the U1255.
Has the drivers seat ever been out of the car?? If so I would suspect that the wiring harness was NOT reinstalled properly attached to the seat base as it was from the factory. Not properly securing the harness can cause the harness to be stretched to its limits of cable length when the seat is moved to extremes of travel. Does your car have and do you use the "easy out" feature which moves the seat to the most rearward position when you exit the vehicle? If so that could be stretching the wiring harness and causing the serial data buss connection to loose contact.
If it were my car I would get my head down as close to the floor in front of the driver seat as possible and examine the seat wiring harness to see if it is being stretched during seat travel........ If it is then check how the harness is secured on the passenger seat (if it has never been out). You may need to secure the wiring of the drivers seat the same way it is for the passenger seat...............
I suspect the cause of this is the Seat Controller Module (SCM) that reported the U1255.
Has the drivers seat ever been out of the car?? If so I would suspect that the wiring harness was NOT reinstalled properly attached to the seat base as it was from the factory. Not properly securing the harness can cause the harness to be stretched to its limits of cable length when the seat is moved to extremes of travel. Does your car have and do you use the "easy out" feature which moves the seat to the most rearward position when you exit the vehicle? If so that could be stretching the wiring harness and causing the serial data buss connection to loose contact.
If it were my car I would get my head down as close to the floor in front of the driver seat as possible and examine the seat wiring harness to see if it is being stretched during seat travel........ If it is then check how the harness is secured on the passenger seat (if it has never been out). You may need to secure the wiring of the drivers seat the same way it is for the passenger seat...............
Steven
