At Fixya.com, our trusted experts are meticulously vetted and possess extensive experience in their respective fields. Backed by a community of knowledgeable professionals, our platform ensures that the solutions provided are thoroughly researched and validated.
do you need to find the body control module (bcm) or Electronic Control module (ecm)do you need to find the body control module (bcm) or Electronic Control module (ecm)
The BCM has nothing to do with the vehicle running...The ECM does...its under the hoodThe BCM has nothing to do with the vehicle running...The ECM does...its under the hood
The BCM most certianly does too, I found a bad BCM on an 00 Durango and once replaced the vehicle started running again. Your comment is like saying a vehicle needs absolutely no grounds to run.The BCM most certianly does too, I found a bad BCM on an 00 Durango and once replaced the vehicle started running again. Your comment is like saying a vehicle needs absolutely no grounds to run.
You can't post conmments that contain an email address.
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Take it to a good local auto-electrician as advised.
Jeff Armer Oct 11, 2021
Have it checked for DTC'S - diagnostic trouble codes , before you start playing with thing's . All the gauge setting information comes to the instrument cluster over serial data network GM Class 2 from the PCM/ECM engine computer . Could have U codes stored, Do you know anything about serial data networks or U codes ? If not, do yourself a favor an have a qualified repair shop check it.
Fuel Gauge
The instrument panel cluster (IPC) displays the fuel level based on information from the engine control module (ECM). The engine control module (ECM) calculates the fuel level based on information from the fuel level sensor. The engine control module (ECM) sends the fuel level information to the body control module (BCM) via the serial data circuit. The instrument panel cluster (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.
Speedometer
The instrument panel cluster (IPC) displays the vehicle speed based on information from the engine control module (ECM). The engine control module (ECM) calculates the vehicle speed from the vehicle speed sensor (VSS) input. The ECM sends a serial data message to the BCM indicating the vehicle speed. The instrument panel cluster (IPC) displays the vehicle speed as received from the BCM via serial data circuit.
The speedometer defaults to 0 km/h (0 mph) when any of the following occur:
• The ECM detects a malfunction in the vehicle speed sensor.
• The BCM detects a loss of serial data communications with the ECM.
• The IPC detects a loss of serial data communications with the BCM.
Every light lit on the instrument cluster , could be data network problem . Do you know what a serial data network is , class 2 or GMLAN ? Hooking up a professional or factory scan tool to view sensor data to ECM - engine computer .
Fuel Gage
The instrument panel cluster (IPC) displays the fuel level as determined by the engine control module (ECM). The IPC receives a serial data message from the ECM indicating the fuel level percent. The fuel gage defaults to empty if:
• The ECM detects a malfunction in the fuel level sensor circuit.
• The IPC detects a loss of serial data communications with the ECM.
When the fuel level is less than a pre-determined value, the IPC illuminates the low fuel indicator.
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.
Doesn't have a fuse just for the gauges . B+ power supply for the whole instrument cluster . Gauge info comes from the BCM - body control module an the PCM - powertrain control modules over serial data network (GMLAN ) The instrument cluster has electronics inside ,plus software . GM did have stepper motor problems in their instrument clusters from 2003 to 2006 . Your best bet , take it to a qualified repair shop. How to repair GM Instrument Cluster Speedometer Gauge Stepper
Engine Coolant Temperature Gage
The engine control module (ECM) sends the coolant temperature to the instrument panel cluster (IPC) via serial data circuit. The IPC receives serial data messages from the BCM indicating the engine coolant temperature. The engine coolant temperature (ECT) gage, if equipped, defaults to 75°C (160°F) or below if:
• The ECM detects a malfunction in the ECT sensor circuit.
• The IPC detects a loss of serial data communications with the ECM.
Refer to Cooling System Description and Operation for more information.
Speedometer
The instrument panel cluster (IPC) displays the vehicle speed based on the information from the engine control module (ECM). The ECM sends a 4,000 pulse per mile signal to the cluster discretely. The IPC calculates the vehicle speed using the time difference between consecutive pulses. The speedometer will default to zero if the time duration since the last speed pulse is greater than or equal to one second.
Fuel Gage Description and Operation
The ECM uses the signal circuits of the primary and secondary fuel level senders to calculate the percentage of fuel remaining in the fuel tank. The ECM supplies 5 volts via the 5 volt reference circuit and also provides a low reference to the primary and secondary fuel level senders. When the fuel tank is full, the resistance of both fuel level senders are high and the ECM senses a high signal voltage on both the signal circuits of the primary fuel level sender and the secondary fuel level sender. When the fuel tank is empty, the resistance of both fuel level senders are low and the ECM senses a low signal voltage on both the signal circuits of the primary fuel level sender and the secondary fuel level sender. The engine control module (ECM) sends fuel level information to the instrument panel cluster (IPC) via serial data circuit. The instrument panel cluster (IPC) displays the fuel level information in the fuel gage. When the fuel level is less than a predetermined value, the low fuel message displays in the driver information center (DIC).
The fuel gage defaults to empty if:
• The ECM detects a malfunction in the fuel level sensor circuit.
• The IPC detects a loss of serial data communications with the ECM.
Does it start an run ? Your best bet is to take it to a ASE certified repair shop ! All the things not working are controlled by the BCM body control module an are on the class 2 serial data bus , would be best to have hooked up to a factory scan tool to see if there are any DTC'S - diagnostic trouble codes stored . The instrument cluster gauge information comes from the PCM / ECM - engine computer over class 2 data bus .
The instrument panel cluster (IPC) displays the fuel level as determined by the engine control module (ECM). The IPC receives a serial data message from the ECM indicating the fuel level percent. The fuel gage defaults to empty if:
The instrument panel cluster (IPC) displays the engine oil pressure as determined by the engine control module (ECM). The IPC receives a serial data message from the ECM indicating the engine oil pressure. The engine oil pressure gage defaults to 0 psi (0 kPa) or below if:
The Body Control Module (BCM) performs multiple body control functions. The BCM can control devices directly connected to its outputs based on input information. The BCM evaluates this information and controls certain body control systems by commanding outputs on or off. The BCM control inputs can be:
?€¢
Sensors and switches that are directly connected to the BCM
?€¢
Class 2 serial data received from other control modules connected to the class 2 serial data link.
The BCM is also capable of controlling other vehicle systems that are not directly wired to the BCM. The BCM does this by sending specific messages on the class 2 serial data link. The control module capable of performing the required function will respond to the BCM message.
You best bet is to take it the dealer or a ASE certified repair shop !
Did you have the vehicle hooked to a factory scan tool to see if it will talk to the scan tool . Your instrument cluster is electronic an has a microprocessor inside , it is connected on the serial data communication network or bus as it is called . It's hard to find a problem when you don't know how it works >
All the gauges in the instrument cluster receive there info from the ECM - BCM engine an body computers on the data bus .
The instrument panel cluster (IPC) displays the vehicle speed based on the information from the engine control module (ECM). The IPC receives a serial data message from the BCM indicating the vehicle speed. PRND321 Display
The instrument panel cluster (IPC) displays the selected gear position as determined by the engine control module (ECM). The IPC receives a serial data message from the ECM indicating the gear position. The PRND321 display blanks if:
?€¢
The ECM detects a malfunction in the transmission range switch 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.
This you should take to a ASE qualified repair facility or the dealer ! It is possible to short out the data bus an bring down the system , meaning nothing on the vehicle will work !
dont know what kind car you have there is a wire that goes to your starter from your ignition its the small thin wire have somebody turn ignition tu run possition and you can go to your starter and get a circuit tester check for power if no power thats your problem easy way to fix is to run new wire to your starter also if ok them your problem is on a fuseble link let me know mayby i can still help by e mailing you a wiring harness diagram ok
All the modules are connected together to communicate with each other via the PCI bus. It is possible that one of the modules is pulling the bus down.Since the vehicle won't start it could be any one of the modules. It will be a process of elimination to find the faulty one by disconnecting them one at a time. Here are a few, powertrain control module (the one you replaced) Instrument cluster, overhead console, anti-lock brakes, airbag. Since the cluster unplugged wont read anymore, just try to start the vehicle to see if that was the one. Otherwise see if the odometer message of "no bus" goes away after each one is unplugged.
where can i find these body control module dakota99 please help ema
do you need to find the body control module (bcm) or Electronic Control module (ecm)
The BCM has nothing to do with the vehicle running...The ECM does...its under the hood
The BCM most certianly does too, I found a bad BCM on an 00 Durango and once replaced the vehicle started running again. Your comment is like saying a vehicle needs absolutely no grounds to run.
×