P0689

ECM/PCM Power Relay Sense Circuit Low

Severity

🔴 High

Can you drive?

Do not drive — repair immediately

Approx. repair cost

$6–111 (est.)

Symptoms

Check Engine Light
Unstable engine operation
Malfunctions of electronic systems
Possible spontaneous engine shutdown
Incorrect on-board diagnostic readings

Causes

Control circuit wire short circuit to ground
Broken or damaged wiring
ECU power relay malfunction
Oxidation or damage to connectors
Internal ECU fault

How to Fix

Read OBD-II codes and record all errors
Locate the control circuit of the ECU power relay according to the diagram
Measure the voltage in the control circuit
Check the wire for short to ground
Check relay and connector
If the circuit is working properly - ECU diagnostics

Related codes

P0685 P0686 P0687 P0688 P0690