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 O: U0253:00
- Refer to MODULE COMMUNICATIONS NETWORK
for schematic and connector information.
Normal Operation and Fault Conditions
The IPMA communicates with the APIM through the FD-CAN, GWM and HS-CAN3.
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition IPMA U0253:00 Lost Communication With Accessory Protocol Interface Module: No Sub Type Information A continuous memory DTC that sets in the IPMA if messages received from the APIM through the GWM are missing for 5 seconds or longer. Possible Sources
- Communication network concern
- APIM
- IPMA concern
- GWM concern
- O1 VERIFY THE CUSTOMER'S CONCERN
- Ignition ON.
- Verify there is an observable symptom present.
Is an observable symptom present?
Yes GO to O2 No CLEAR the DTC. The system is operating normally at this time. The DTC may have been set due to high network traffic or an intermittent fault condition. - O2 VERIFY THAT THE DIAGNOSTIC SCAN TOOL COMMUNICATES WITH THE APIM (SYNC MODULE)
- Connect a diagnostic scan tool.
- Check that a vehicle session can be established using the diagnostic scan tool.
Can a vehicle session be established?
Yes GO to O3 No REFER to: Controller Area Network (CAN) Module Communications Network . REFER to: Ethernet Module Communications Network . - O3 PERFORM THE IPMA (IMAGE PROCESSING MODULE A) SELF-TEST
- Using a diagnostic scan tool, perform the IPMA self-test.
- Clear the Diagnostic Trouble Codes (DTCs).
- Wait 10 seconds.
- Repeat the IPMA self-test.
Are any non-network Diagnostic Trouble Codes (DTCs) present?
Yes DIAGNOSE all non-network Diagnostic Trouble Codes (DTCs). REFER to the IPMA DTC Chart. No GO to O4 - O4 PERFORM THE APIM (SYNC MODULE) SELF-TEST
- Using a diagnostic scan tool, perform the APIMKOEO self-test.
Are any non-network Diagnostic Trouble Codes (DTCs) present?
Yes DIAGNOSE all non-network Diagnostic Trouble Codes (DTCs). REFER to: Information and Entertainment System . No GO to O5 - O5 PERFORM THE GWM (GATEWAY MODULE A) SELF-TEST
- Using a diagnostic scan tool, perform the GWM self-test.
Are any Diagnostic Trouble Codes (DTCs) recorded?
Yes SEE the GWM DTC Chart. REFER to: Controller Area Network (CAN) Module Communications Network . REFER to: Ethernet Module Communications Network . No GO to O6 - O6 RECHECK THE IPMA (IMAGE PROCESSING MODULE A) DIAGNOSTIC TROUBLE CODES (DTCS)
- Using a diagnostic scan tool, clear the IPMA Diagnostic Trouble Codes (DTCs).
- Ignition OFF.
- Ignition ON.
- Wait 10 seconds.
- Using a diagnostic scan tool, perform the continuous memory self-test.
- Check the IPMA Diagnostic Trouble Codes (DTCs).
Is DTC U0253:00 still present?
Yes GO to O7 No The system is operating correctly at this time. This DTC may have been set due to high network traffic or an intermittent fault condition. - O7 CHECK FOR OTHER CAUSES OF COMMUNICATION NETWORK CONCERNNOTE: If new modules were installed prior to the DTC being set, the module configuration may be incorrectly set during the PMI, or the PMI may not have been carried out.
- CHECK the vehicle service history for recent service actions related to the APIM, IPMA or GWM. If recent service history is found:
- verify correct replacement module was installed
- HVBOM may be used to verify correct part fitment
- verify the configuration of replacement module was correct
- re-configure module using as-built data if prior configuration is suspect
- verify the module was not obtained from a like vehicle and installed into customer vehicle
- return the swapped module to source vehicle and obtain new replacement module
- verify correct replacement module was installed
- Operate the system and determine if the observable symptom is still present.
Is the observable symptom still present?
Yes GO to O8 No The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration. - CHECK the vehicle service history for recent service actions related to the APIM, IPMA or GWM. If recent service history is found:
- O8 CHECK FOR CORRECT APIM (SYNC MODULE) OPERATION
- Ignition OFF.
- Disconnect and inspect all APIM 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 the APIM module 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, REFER to: Information and Entertainment System . No The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. 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.