This is a good possability, test the brake lite switch to see if you have power coming out when the brake is applied. if you do then you will need o trace the wiring back to the lite socket ( pig tail ). Good luck and remember to rate all replies you get. Thanx.
you need to go back over all the bulbs. Take each one out and put it back in making sure its working properly. Most likely a bulb is not grounding. I had this on a f-150 that took two days to track down. Good luck
Probably the flasher, which is usually a small, round can-shaped device with two electrical prongs, usually located near your fuses underneath the dash. Can get these at an auto parts store for $5-10.
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I'm receiving a No communication with ECM code when I hook up my OBD2 ? What do you have ,cheap code reader ? Need a professional grade type - one that will read codes - communicate with all the modules on the vehicle . BCM, ABS , SRS , Instrument cluster ,HVAC , Radio etc... One of those or all will have U codes stored , a wiring diagram is going to help you . Do you know what U codes are ? instead of grounds is there battery voltage at pin 16 in DLC ?
Doesn't have one , the BCM - body control module supply's voltage to the brake light's . Brake pedal position sensor is a input to the BCM .The BCM has battery voltage supplied from BCM fuse IBCM 1 fuse -fuse #20 30 amp ,located in the under hood fuse box.
Stop Lamps
The body control module (BCM) is responsible for controlling the stop lamps. When the driver presses the brake pedal, the BCM will receive a signal from the brake pedal position sensor. The BCM then supplies battery positive voltage to both left and right stop lamp assemblies and to the center high mounted stop lamp (CHMSL). The stop lamps are grounded at G401 and G403. The CHMSL is grounded at G302.
The brake pedal position sensor receives a low reference signal and a 5-volt reference signal from the BCM. Whenever the brake pedal is applied, the brake pedal position sensor applies a variable voltage signal to the BCM through the stop lamp switch signal circuit. Brake pedal position sensor calibration must be performed after the brake pedal position sensor or body control module (BCM) have been serviced. The calibration procedure will set brake pedal position sensor home value. This value is used by the BCM to determine the action of the driver applying the brake system and to provide this information to the vehicle subsystems via the class 2 communication bus.
Hooking up a factory or someother professional type scan tool an checking for DTC'S - diagnostic trouble codes in the BCM would be a good idea . If the brake light's are not working .
Why do you want to change the BCM ? What problems are you having ? Your best bet , have a qualified technician hook up a scanner an read code's .Your vehicle doesn't even have a BCM .
Module Controlled Functions
The multifunction modules consist of the following:
air suspension module
driver door module (DDM)
lighting control module (LCM)
The air suspension module is linked to its own data link connector (DLC). The air suspension module controls the air suspension system and the electronic variable orifice (EVO) steering.
The DDM is connected to the international standards organization (ISO) 9141 communication network. The DDM controls many functions including power door locks and remote keyless entry (RKE).
The LCM is connected to the ISO 9141 communication network. The LCM controls both interior and exterior lighting, backlighting, the battery saver and warning chimes.
Do yourself a favor an take it to a qualified repair shop.
U codes are for communication problems between control module's . What BCM code ? U0111
Data bus: battery energy control module A - no communication
http://www.troublecodes.net/ucodes
I wouldn't do that given the complexity of electronic modules an data bus communication networks on this vehicle . Disconnecting batteries can cause modules to go to sleep an not wake back up . The ignition switch is an input to the BCM - body control module , the BCM turns on relays powering up systems on the vehicle .
The BCM executes the high power mode by grounding the controlled power relay coil control circuit of the CONTROLLED POWER relay whenever the BCM is awake. This circuit also is grounded for 15 minutes after you turn the ignition switch to the LOCK position in order to obtain the RAP function. After 15 minutes elapse, the BCM enter a sleepstate and transitions to the low power mode. The components under controlled power then receive any necessary voltage from the battery positive voltage circuit of the BCM. If the BCM is in the low power mode, and the BCM detects that the current exceeds approximately 2 amperes, the BCM wakes up and re-enters the high power mode. If the vehicle remains inactive with the ignition in the LOCK position and without any BCM wake-ups for a period of 3 days, the BCM deactivates the low power mode. The following components are under controlled power: There are probably DTC'S - diagnostic trouble codes stored in the BCM . A simple code reader can not read these , an has nothing to do with the check engine light . Battery Disconnect or Replacement Problems You may have been lucky so far disconnecting the battery .
Disconnect batt see if it clears. Or unplug computr..clean connection pins...see if unit reboots. Dirty brake fluid can ruin abs module. To pinpoint du a datastream w a factory scantool and not at a dealer. Code readers dont give u numbrs for decision.
Well Gary , you should have it checked for DTC'S - diagnostic trouble codes . Not at a part's store , thier diagnostic tool only checks engine computer codes ! Your vehicle has a number of control modules , PCM/ECM - engine , BCM - body , ABS , Air bag , the instrument cluster has a microprocessor inside , an can set DTC'S as well. But the only way to read codes in most of these modules is with a professional type scan tool . The warning lights come on when you turn the key on as a bulb check an to let you know those systems are functioning . Could be your instrument cluster is defective or a communication network problem , do you know what a serial data bus or communication network is ? This is what the control modules share information on . Your 03 chevy has the IPC bus for data transfer from the BCM to the IPC . U codes are communication error codes .
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
U2000
The IPC determines that the BCM transmitted data to the IPC is invalid for greater than 12 seconds. The IPC sends a message to the BCM via the SPI serial data in circuit indicating that invalid data was received.
U2001
The BCM determines that the IPC transmitted data to the BCM is invalid for greater than 5 seconds.
U2002
The BCM detects that the SPI serial data in circuit is less than 1.2 v for greater than 5 seconds.
U2003
The BCM detects that the SPI serial data in circuit is greater than 4.5 v for greater than 5 seconds.
U2004
The BCM detects that the SPI serial data out circuit is less than 1.2 v for greater than 5 seconds.
U2005
The BCM detects that the SPI serial data out circuit is greater than 4.5 v for greater than 5 seconds.
U2006
The BCM detects that the SPI serial data clock circuit is less than 1.2 v for greater than 5 seconds.
U2007
The BCM detects that the SPI serial data clock circuit is greater than 4.5 v for greater than 5 seconds.
Your vehicle also uses class 2 data bus .
Class 2 Serial Data Link
The class 2 serial data link allows the following modules to communicate with each other:
• The body control module (BCM)
• The electronic brake control module (EBCM)
• The integrated radio chassis (IRC)
• The powertrain control module (PCM)
• The Remote Control Door Lock Receiver (RCDLR)
• The inflatable restraint sensing and diagnostic module (SDM)
The class 2 serial data link allows a scan tool to communicate with the above modules for diagnostic and testing purposes.
Given the complexity of your vehicle , all the control modules , serial data communication network. Having the vehicle scanned for DTC'S - diagnostic trouble codes , not a code reader or at a auto parts store . A professional type tool is need to pull codes from BCM - body computer , Instrument cluster .
Fuel Gage
The IPC displays the fuel level as determined by the PCM. The body control module (BCM) receives a class 2 message from the PCM indicating the fuel level percent. The BCM converts the fuel level percent into a percent gage deflection. The IPC receives a message from the BCM via the serial peripheral interface (SPI) indicating the requested gage position. The fuel gage defaults to E (empty) if:
• The PCM detects a malfunction in the fuel level sensor circuit.
• The BCM detects a loss of class 2 communications with the PCM.
• The IPC detects a loss of SPI communications with the BCM.
When the fuel level is less than a pre-determined value, the low fuel indicator illuminates.
Could have U- codes , communication network problems .
DTC U1000 and U1255
Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the ID number of the module which sent the message for State of Health monitoring, Node Alive messages. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. When a module does not associate an ID number with at least one critical parameter within about 5.5 seconds of beginning serial data communication, DTC U1000 or U1255 is set. When more than one critical parameter does not have an ID number associated with it, the DTC will only be reported once.
The table below list the modules on the Class 2 Serial Data Circuit that will set a U1000 or U1255 and should be actively communicating the previously described messages on the Class 2 Serial Data Circuit.
Sounds like a blown fuse to one of the computers, either the ECM (engine control computer) or the BCM (body control computer). The ECM fuse should be under the hood and the BCM fuse in the cabin. The U1064 means a loss of communication on the data line between computers (64 usually is the BCM). If the computers can't communicate they will shut down the engine and set trouble codes. The other issue could be a faulty ignition switch not allowing power to a computer (but not common for cavaliers or sunfires). If fuses are good, chances are you have a faulty computer somewhere in the data line, shorting out communication.
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