Detailed Description of Error P066A

OBDII error code P066A indicates that the Engine Control Module (ECM) has detected a low voltage condition in the cylinder 1 glow plug control circuit. The glow plug control circuit is responsible for providing power to the glow plugs, which are used to assist in the combustion process during cold engine starts.

In diesel engines, glow plugs are used to pre-heat the combustion chamber, allowing for easier engine starting and reduced emissions. The ECM monitors the voltage in the glow plug control circuit to ensure it is within the specified range. If the voltage is lower than expected, the ECM will set code P066A and illuminate the Check Engine Light (CEL).

Possible Causes of Error P066A

• Faulty glow plug or glow plug relay
• Wiring or connector issues in the glow plug control circuit
• Low battery voltage or weak battery
• ECM malfunction or software issue
• Corrosion or water damage in the glow plug control circuit
• Faulty fuel injector or fuel injector circuit
• Engine mechanical issues, such as low compression or engine oil leaks

Possible Fixes for Error P066A

• Check the glow plug and glow plug relay for signs of wear or damage, and replace if necessary
• Inspect the wiring and connectors in the glow plug control circuit for signs of damage or corrosion, and repair or replace as needed
• Check the battery voltage and charging system to ensure they are functioning properly
• Use a scan tool to monitor the glow plug control circuit voltage and compare it to the manufacturer''s specifications
• Consult the repair manual for specific troubleshooting procedures and repair information
• Consider seeking the assistance of a professional mechanic if the problem persists