U023A — Lost Communication With Image Processing Module A

Diagnostic algorithm

1. Confirm U023A is current and note freeze frame and time of occurrence. Check for additional codes in all modules.
2. Attempt to communicate with the IPM using a dealer-level or capable scan tool. If the tool cannot address the module, proceed to physical checks.
3. Inspect connectors and wiring at the IPM and camera(s). Unplug/replug connectors and inspect contacts for corrosion or damage.
4. Verify IPM power and ground with a DMM (key on). Check related fuses and relays. Repair any open circuits.
5. With ignition on, use a scan tool or scope to view network traffic at the IPM connector. Look for normal message traffic or bus faults/absence.
6. Check termination resistances on the bus and inspect for shorts to battery or ground on CAN/LIN/Ethernet lines.
7. If network traffic is absent only at the IPM, trace wiring to junctions and test continuity to the main bus. Repair damaged wiring.
8. If bus is active but IPM does not respond, attempt a software update/reflash per OEM procedures. Reprogram or replace if update fails.
9. If an intermittent fault is suspected, perform wiggle tests on harnesses while monitoring the bus and codes; secure/repair as required.
10. After repairs or module replacement, clear codes, perform required calibrations (camera alignment) and road test to confirm resolution.
11. If fault persists, isolate by disconnecting other modules or modules recently serviced to identify bus conflicts, or consult OEM technical support.