U069E: Lost Communication With Coolant Heater A

What it means

Communication with coolant heater A has been lost. The code identifies a communication fault; the heater’s function and the vehicle’s response depend on the vehicle design.

At a glance

• Usually lights the warning light of the system that lost communication

How it works

Coolant Heater A is a vehicle-controlled heater that warms coolant on designs equipped with this system. U069E is set when the control network no longer receives messages from heater A, so the heater may be unavailable and cold-weather warm-up or related functions may be affected.

Common causes

Most likely first.

1. Bus wiring open or shorted
2. Module without power or ground
3. Module failed

Symptoms

• Multiple warning lights may illuminate
• Affected modules may go into limp mode or shut down
• Specific functions inoperative depending on module
• Diagnostic tools may show communication faults

How to diagnose it

1. Scan all modules and review freeze-frame data to establish when communication with Coolant Heater A was lost and whether other network faults occurred at the same time.
2. Check scan-tool status for Coolant Heater A and note any heater-specific codes from the module that controls it.
3. Inspect the heater connector and harness for looseness, corrosion, chafing, or heat or water damage.
4. Check the heater module's power and ground circuits, including relevant fuses, against the manufacturer's specification.
5. Test the communication bus wiring for opens or shorts using the manufacturer's procedure before concluding the heater module has failed.

Common fixes

• Reconnect the Coolant Heater A connector or repair damaged wiring.
• Replace a blown fuse after checking for the cause, or repair the heater module's power or ground connection.
• Repair an open or short in the communication bus to Coolant Heater A.
• Replace the heater module if its wiring, power, and ground are correct but communication remains absent.

Can I keep driving?

The vehicle may remain drivable, but coolant heating may be unavailable, which can increase warm-up time or reduce cold-weather comfort and related functions. Avoid relying on the heater in very cold conditions until it is checked.