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If your Chevrolet Captiva has lost communication with the Body Control Module (BCM) and won't start, here are a few steps you can take to try and fix the issue:
1. Check the BCM connections: Make sure the BCM is properly connected to the wiring harness and that there is no corrosion or damage to the connectors. Disconnect the BCM and clean the connectors with electrical contact cleaner if necessary.
2. Check the battery: Make sure the battery is fully charged and that the terminals are clean and tight. A weak or dead battery can cause communication issues between the various modules in the vehicle.
3. Reset the BCM: Try resetting the BCM by disconnecting the battery cables for 10 minutes, then reconnecting them. This may help clear any communication errors and allow the BCM to communicate with other modules in the vehicle.
4. Have the BCM reprogrammed: If none of the above steps work, you may need to have the BCM reprogrammed or replaced. A dealership or qualified repair shop should be able to diagnose the issue and perform the necessary repairs.
It's important to note that communication issues between modules can be complex and difficult to diagnose, so it's often best to seek the assistance of a qualified mechanic or dealership for repairs.
First off you would need to know from where an how this data get's to the instrument cluster , Computers involved ( control module's ) etc... serial data network - how the computers (modules ) communicate . Special tool's involved in testing this data - factory or professional scan tool - to view data from sensor's - temp sensor , fuel level sending unit in the fuel tank . Both of the these sensors are input's to the PCM/ECM - engine computer , which shares this info to other module's which need this info. The GMLAN serial data network is the data network which does this .
The instrument cluster has a microprocessor inside which view's this data an controls stepper motors to drive the gauge need .
Not working correctly or not at all can becaused by any number of thing's . The instrument cluster could have DTC'S - diagnostic trouble code's stored . Auto part stores can not read these code's or BCM code's . .
Engine Coolant Temperature Gage
The engine control module (ECM) calculates the engine coolant temperature as determined by the coolant temperature sensor. The ECM sends the engine coolant temperature to the body control module (BCM) via the serial data circuit. The instrument panel cluster (IPC) displays the engine coolant temperature when the BCM sends a serial data message to the IPC indicating the engine coolant temperature. The engine coolant temperature gage defaults to 0° or below if:
• The ECM detects a malfunction in the engine coolant temperature sensor circuit.
• The IPC detects a loss of serial data communications with the BCM.
• The BCM detects a loss of serial data communications with the ECM.
Fuel Gage
The engine control module (ECM) sends the fuel level percent to the BCM via the serial data circuit. The IPC displays the fuel level as received from the BCM. The fuel gage defaults to E (empty) if:
• The ECM detects a malfunction in the fuel level sensor circuit.
• The IPC detects a loss of serial data communications with the BCM.
• The BCM detects a loss of serial data communications with the ECM.
When the fuel level is less than a pre-determined value, the Low Fuel indicator message illuminates.
Your best bet , take your vehicle to a qualified repair shop.
Will not spin over ? When you turn the key to start ,the starter doesn't engage an spin the engine ? Dash light's come , headlamps come on bright ? Battery good , charged ? No codes ? just engine ,OBD 2 codes ? BCM codes ? How or what did you use to check codes ? code reader , scan tool ? A professional type that can read BCM - body control module codes ? Do you have any idea how complex the electronic's are on this vehicle ? Do you know what happen's when you turn the key to start ?
Power Mode Master
This vehicle body control module (BCM) functions as the power mode master (PMM). The ignition switch is a low current switch with multiple discrete ignition switch signals to the PMM for determination the power mode that will be sent over the serial data circuits to the other modules that need this information, and so the PMM will activate relays and other direct outputs of the PMM as needed. Refer to Power Mode Description and Operation for a complete description of power mode functions.
The body control system consists of the body control module (BCM), communications, and various input and outputs. Some inputs, outputs and messages require other modules to interact with the BCM. The BCM also has discrete input and output terminals to control the vehicle's body functions. Battery positive voltage is provided to the BCM from the BCM fuse in the underhood fuse block. The module has two grounds at G 202 as well as one directly to the vehicle battery. The BCM is wired to the GMLAN High speed serial data buss and the GMLAN Low speed serial data buss and acts as a gateway between them. If the BCM does not communicate the vehicle will not start due to the inability of the engine/powertrain control module (ECM/PCM) and vehicle theft deterrent (VTD) control module to communicate without the BCM providing the gateway function.
Gateway
The body control module (BCM) in this vehicle functions as a gateway or translator. The purpose of the gateway is to translate serial data messages between the GMLAN high speed buss and the GMLAN low speed buss for communication between the various modules. The gateway will interact with each network according to that network's transmission protocol.
One example of this necessary communication is the communication between the engine/powertrain control module (ECM/PCM) which is high speed serial data and vehicle theft deterrent (VTD) control module which is low speed serial data. If these modules can not exchange information, the vehicle will not start.
All communication between the BCM and a scan tool is on the High speed GMLAN serial data circuits. A lost communication DTC typically is set in modules other than the module with a communication failure.
If you don't know of any of this ,your best bet , take it to a qualified repair shop.
I'm just curious if your aware of the BCM function's on your vehicle an if you know what the gate way module is ? An do you know about serial data communication between modules ? An do you know what the power mode master is ? And do you know the BCM needs programming ?
The body control module (BCM) in this vehicle functions as a gateway or translator. The purpose of the gateway is to translate serial data messages between the GMLAN high speed buss and the GMLAN low speed buss for communication between the various modules. The gateway will interact with each network according to that network's transmission protocol.
One example of this necessary communication is the communication between the engine control module (ECM)/powertrain control module (PCM) which is high speed serial data and Theft Deterrent Module which is low speed serial data. If these modules can not exchange information, the vehicle will not start.
Communication between the BCM and a scan tool can be on the high speed GMLAN network or low speed GMLAN network. If one network is lost, the BCM can still communicate with the scan tool. A lost communication DTC typically is set in modules other than the module with a communication failure.
The U110C is a BUS Message and usually has to do with both PCM and BCM, because its a lose of BUS Signal between the PCM and the BCM.
FIRST THING TO TRY:
The first thing I would try is remove the negative battery cable for 20 seconds then replace it. NEXT: Start the engine several times then let idle for 10 to 20 minutes then start it several more times and if the code doesn't return and the check engine light stays out, simple drive it for awhile like you normally would. If the code come right back, below is some common problems.
COMMON CAUSES of U110C:
(1) Communication with BCM is lost / See if you can communicate with the BCM.
(2) PCI Bus Circuit open between PCM and BCM / Check the positive and negative bus signal at both the PCM and BCM.
(3) BCM
(4) PCM
(5) Fuel Level Bus Message is missing
Obviously, all these issues must be tested to see which one is causing the problem. BUT first try the battery cable removal and see what happens.
Let me know the out come and I'll try to help further.
Hope this helps and have an awesome day!
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.
U110C-NO FUEL LEVEL BUS MESSAGE When Monitored and Set Condition: U110C-NO FUEL LEVEL BUS MESSAGE When Monitored: Ignition on. Set Condition: No fuel level BUS messages received by the PCM for 20 seconds. POSSIBLE CAUSES DTC RESET COMMUNICATE WITH BCM FUEL LEVEL BUS MESSAGE PCI BUS CIRCUIT OPEN FROM PCM TO BCM BCM TEST ACTION APPLICABILITY 1 NOTE: If a fuel level circuit or performance DTC is set along with P1681, diagnose the circuit/performance DTC before continuing. Turn the ignition on. With the DRBIIIt, erase DTCs. Start the engine on and off several times. Leave the engine running for at least 20 second each time. With the DRBIIIt, read DTCs. Does the DTC reset? All Yes ! Go To 2 No ! Refer to the INTERMITTENT CONDITION symptom in the Driveability category. Perform POWERTRAIN VERIFICATION TEST VER - 1 - NGC. 2 Ignition on, engine not running. With the DRBIIIt, attempt to communicate with the BCM. Can communication be established with the BCM? All Yes ! Go To 3 No ! Refer to the Communication Category and perform the appropriate symptom related to no communication with BCM. Perform POWERTRAIN VERIFICATION TEST VER - 1 - NGC. 3 Turn the ignition on. Using the DRBIIIt, read the Fuel Level parameter in the PCM. Does the DRBIIIt display a fuel level value? All Yes ! Replace and program the Powertrain Control Module in accordance with the Service Information. Perform POWERTRAIN VERIFICATION TEST VER - 1 - NGC. No ! Go To 4 287 DRIVEABILITY - NGC TEST ACTION APPLICABILITY 4 Turn the ignition off. Disconnect the PCM harness connectors. Disconnect the BCM harness connector. CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS. Measure the resistance of the PCI Bus circuit from the BCM harness connector to the appropriate terminal of special tool #8815. Is the resistance below 5.0 ohms? All Yes ! Replace BCM in accordance with the Service Information. Perform POWERTRAIN VERIFICATION TEST VER - 1 - NGC. No ! Repair the PCI Bus circuit between the PCM and the BCM for an open. Perform POWERTRAIN VERIFICATION TEST VER - 1 - NGC __________________
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