Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Pinpoint Test Q: U0256:87
- Refer to MODULE COMMUNICATIONS NETWORK
for schematic and connector information.
Normal Operation and Fault Conditions
REFER to: Communications Network - System Operation and Component Description .
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition BCM U0256:87 Lost Communication With Front Controls Interface Module 'A': Missing Message A continuous memory DTC that sets in the BCM if messages received from the FCIM through the GWM are missing. Possible Sources
- Communication network concern
- Battery voltage concern
- GWM concern
- FCIM
- BCM
- Q1 CHECK THE COMMUNICATION NETWORK
- Ignition ON.
- Connect the diagnostic tool.
- Using a diagnostic scan tool, perform a network test.
Does the FCIM pass the network test?
Yes GO to Q2 No REFER to: Communications Network . - Q2 CHECK THE BCM (BODY CONTROL MODULE) CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODES (CMDTCS)
- Using a diagnostic scan tool, clear the Diagnostic Trouble Codes (DTCs).
- Wait 10 seconds.
- Using a diagnostic scan tool, check the BCM CMDTCs.
Is DTC U3006:16, U3006:17, U3007:16, U3007:17, U3013:16, U3013:17, U3014:16 or U3014:17 recorded?
Yes For DTC U3006:16, U3007:16, U3013:16 or U3014:16, GO to Pinpoint Test V For DTC U3006:17, U3007:17, U3013:17 or U3014:17, GO to Pinpoint Test W No GO to Q3 - Q3 RETRIEVE THE FCIM (FRONT CONTROLS INTERFACE MODULE) DTCS
- Using a diagnostic scan tool, perform the FCIM self-test.
Are any FCIM DTCs present?
Yes REFER to: Information and Entertainment System . No GO to Q4 - Q4 RECHECK THE BCM (BODY CONTROL MODULE) CMDTCS
- Using a diagnostic scan tool, clear the DTCs.
- Wait 10 seconds.
- Using a diagnostic scan tool, check the BCM CMDTCs.
Is DTC U0256:87 present?
Yes GO to Q5 No The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition. - Q5 CHECK FOR DTC (DIAGNOSTIC TROUBLE CODE) U0256:87 SET IN OTHER MODULES
- Using a diagnostic scan tool, clear the DTCs.
- Ignition OFF.
- Ignition ON.
- Wait 10 seconds.
- Using a diagnostic scan tool, retrieve all
CMDTCs.
Is DTC U0256:87 set in other modules?
Yes GO to Q6 No GO to Q7 - Q6 CHECK FOR CORRECT FCIM (FRONT CONTROLS INTERFACE MODULE) OPERATION
- Disconnect and inspect all FCIM connectors.
- Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary
- Reconnect all FCIM connectors. Make sure it seats and latches correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new FCIM. Refer to the appropriate Information and Entertainment System article. No The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues. - Q7 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION
- Disconnect and inspect all BCM connectors.
- Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary
- Reconnect all BCM connectors. Make sure they seat and latch correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new BCM. Refer to Body Control Module (BCM) No The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.