P06D4

Symptoms

• False sensor error codes with "Circuit High" reading
• Incorrect engine operation - over-rich or over-lean mixture
• Check Engine Light Is On
• Unstable idle speed
• Possible transition to emergency mode

Causes

• Internal fault of the ECU reference voltage source
• Circuit E wire shorted to high voltage source
• Damage to wiring insulation
• Malfunction in the ECU ground circuit
• Overvoltage in the vehicle's on-board network

How to Fix

1. Measure the actual voltage of circuit E with the ignition on
2. Check if the reading matches the norm of 5 V
3. Examine the wiring diagram to identify sources that may be causing increased voltage on circuit E
4. Check the insulation of the reference voltage wire along its entire length
5. Check the quality of the ECU grounding
6. If the wiring is correct, send the ECU for diagnostics.

Related codes

Error P06D4 by Vehicle Brand