U063E

Code

Generic U — Network/User

Lost Communication With Exhaust Heat Exchanger Bypass Valve Actuator A

Brand: Generic

Type: U — Network/User

Views: UK: 20 EN: 28 RU: 22

AI status

Completed

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Page language: EN

Causes

Open or short in wiring between controller and bypass valve actuator
Poor or corroded connector(s) at actuator or control module
Failed bypass valve actuator or internal electronics
Loss of power or ground to the actuator
CAN/communication bus fault (bus off, short to battery/ground)
Faulty control module or software/firmware issue

Symptoms

DTC U063E stored and MIL (check engine light) may be illuminated
Exhaust heat management features inoperative or limited (longer warm-up)
Diagnostic scanner shows no response or stale data from actuator
Intermittent faults or other network-related DTCs present
Possible reduced engine or aftertreatment performance warnings

What to check

Retrieve freeze frame and related codes with a scan tool; note network error counts
Verify battery voltage (key on, engine off) and ground quality
Visually inspect wiring and connectors for damage, heat exposure, corrosion
Check for applicable fuses and relays feeding the actuator
Check other modules on the same CAN/communication bus for communication issues
Monitor live data for actuator status and CAN message presence using a diagnostic tool

Signal parameters

Supply voltage to actuator: nominal battery voltage (~11–14 V with key on/engine running)
Ground continuity: near 0 ohms between actuator ground and chassis ground
CAN/communication bus differential voltage: approx. 2.5 V idle on each CAN line (verify with scope)
Expected periodic status messages from actuator: present/regular when healthy (use OEM scanner to confirm)
Actuator coil/motor resistance: specific to design (compare to manufacturer specification)

Diagnostic algorithm

Connect a capable scan tool, read all stored and pending codes, and record live data related to the Exhaust Heat Exchanger Bypass Valve Actuator A and the CAN bus.
Attempt to actuate the bypass valve from the scan tool while watching live data. Note if there is no response or communication failure.
Perform a visual inspection of the actuator, connector, and harness for heat damage, chafing, pin corrosion, or water intrusion. Repair any obvious damage.
Verify power and ground at the actuator connector with key on. Check for battery voltage on the supply pin and continuity of ground to chassis. Repair wiring or fuses as needed.
Check for CAN/communication signals at the actuator connector (or nearest junction) using an oscilloscope or CAN diagnostic tool. Look for differential waveform and periodic messages. If the bus is silent or shows bus-off, trace to other modules and junctions.
Wiggle test the harness while monitoring the scan tool to try to reproduce the fault—look for intermittent reconnection or data restoration.
If power/ground and CAN are present but no communication with the actuator, unplug the actuator and measure actuator internal resistance per OEM spec. If out of spec, bench-test or replace the actuator.
If the actuator bench-tests good, inspect intermediate modules, gateways, and splice points on the network. Swap or reflash suspect modules only after confirming wiring integrity.
After repairs, clear codes and retest for proper operation and that the DTC does not return. If intermittent, road test under conditions that previously produced the fault.
Refer to vehicle-specific wiring diagrams and OEM service information for pinouts, message IDs, and advanced CAN diagnostics if issue persists.