U0115

Lost Communication With ECM/PCM B

Severity

🔴 High

Can you drive?

Do not drive — repair immediately

Approx. repair cost

$56–333 (est.)

Symptoms

Engine won't start
Engine failures
Check Engine Light Is On
Power Loss
Incorrect dashboard readings

Causes

Open or short circuit in the CAN bus circuit
Poor contact in ECU connectors
Control unit (ECM/PCM) malfunction
Problems with module power supply
Contact corrosion

How to Fix

Check the integrity of the CAN bus and the condition of the connectors
Diagnose the control unit (ECM/PCM)
Check fuses and relays related to ECU power supply
Clean contacts from corrosion
If necessary, replace damaged ECU

Related codes

U0100 U0121 U0140