What it means
Generic U0159 means peers (IPC/BCM/radio) stopped receiving messages from the parking assist control module (ultrasonic/park-aid ECU). Usually on body CAN (Ford MS-CAN, GM Low-Speed GMLAN) bridged to HS-CAN via BCM. OBD-Codes.com
Typical symptoms
- “Check Park Aid”/park-assist inoperative; chimes disabled or erratic
- Code often appears after bumper/repair/water intrusion; PAM offline on topology. RepairPal.com
Why it sets
- Timeout on PAM messages from reporting nodes (IPC/BCM/radio) after a calibrated interval. Battery low/ignition transients may set history codes, but active U0159 indicates a current comm loss. OBD-Codes.com
Common root causes
PAM feed/ground loss; body-bus wiring damage in rear bumper/kick panel; single-wire GMLAN splice-pack issues; module water intrusion; aftermarket trailer/park-aid wiring conflicts. OBD-Codes.com
Professional diagnostics
Global scan/topology; verify PAM enumerates; load-test feeds/grounds; match physical layer (MS-CAN ≈60 Ω pair; single-wire GMLAN uses 0–5 V checks, not 60 Ω); isolate branch; inspect bumper harness/connectors; software/part last. NHTSA Static
Verified fixes
Restore PAM power/grounds; repair harness/connectors; correct MS-CAN/GMLAN faults; remove accessory conflicts; update or replace/initialize PAM; clear, operate (reverse/park-aid), re-scan.
Sources
- OBD-Codes – U0159 (definition & diagnostics). OBD-Codes.com
- RepairPal – U0159 (symptoms/causes). RepairPal.com
- GM/ACDelco – HS-LAN Tips (for HS-side checks & general network spec). NHTSA Static