Damaged, corroded, or disconnected wiring at the park assist module connector; Failed park assist module (internal communication fault or water intrusion); Blown fuse or poor ground connection serving the park assist module; CAN bus or dedicated serial data line open or shorted between the module and the gateway; Corrosion or water damage in a rear bumper harness connector or sensor splice; Software or configuration mismatch after battery replacement or module swap; Failed gateway or body control module preventing message routing (less common)

DTC codes / C06xx · Brakes, steering and suspension / C0620

C0620Park Assist Module Communication

Q: What does code C0620 mean?

Park Assist Module Communication. C0620 is a chassis code indicating that the park assist module (the dedicated computer that controls the parking sensors and warning alerts) has lost or never established reliable communication on the vehicle's data bus. The module itself may be powered and grounded, but the body control module or gateway cannot exchange messages with it, so the system sets this fault and typically disables park assist features.

C0620 is a chassis code indicating that the park assist module (the dedicated computer that controls the parking sensors and warning alerts) has lost or never established reliable communication on the vehicle's data bus. The module itself may be powered and grounded, but the body control module or gateway cannot exchange messages with it, so the system sets this fault and typically disables park assist features.

SystemChassis

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaBrakes, steering and suspension

Symptoms you may notice

Park assist warning light or message on the dashboard, often with a chime
Parking sensors produce no audible or visual alerts when maneuvering at low speed
Park assist system appears completely inactive, with no distance indications
Intermittent park assist operation that comes and goes with temperature or vibration
Often no symptoms besides the warning light, especially if the driver never relies on park assist
Other unrelated electrical gremlins if the fault lies on a shared communication bus

Common causes, most likely first

Damaged, corroded, or disconnected wiring at the park assist module connector
Failed park assist module (internal communication fault or water intrusion)
Blown fuse or poor ground connection serving the park assist module
CAN bus or dedicated serial data line open or shorted between the module and the gateway
Corrosion or water damage in a rear bumper harness connector or sensor splice
Software or configuration mismatch after battery replacement or module swap
Failed gateway or body control module preventing message routing (less common)

How to diagnose and fix it

Scan all modules for communication codes and record which modules can and cannot be reached
Check the park assist module fuse and verify battery voltage and ground at the module connector
Inspect the module connector and rear bumper harness for corrosion, water intrusion, or pushed pins
Measure resistance and continuity on the communication bus wires between the module and the gateway
Perform a wiggle test on harnesses while watching live data for intermittent communication dropouts
If wiring and power are good, substitute a known-good module or reflash/configure the existing module
Clear codes and verify park assist operation with a road test and live sensor data

Communication codes are not always module failures

A single failed park assist sensor can sometimes pull the communication line low and set a module communication code, so always check sensor wiring before condemning the module.
Water intrusion into the rear bumper harness is a frequent hidden cause, especially after bodywork or a rear-end impact that pinched the loom.
The park assist module often shares a bus segment with other rear-end modules, so a single chafed wire can set multiple communication codes that look unrelated.
After replacing the park assist module, many vehicles require configuration or a software flash, and skipping that step will leave C0620 stored even with good hardware.
A weak battery or poor ground can cause the module to drop off the bus intermittently, so load-test the battery and clean ground points before replacing parts.

Can I keep driving with C0620?

The vehicle remains safe to drive because park assist is a convenience feature, but you should not rely on parking sensors and should use mirrors and direct observation when maneuvering. Avoid extended driving with the warning active if you notice other electrical symptoms, and have the fault diagnosed soon to prevent a simple wiring repair from becoming a module replacement.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.