Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

ECT4 Check SIGRTN Circuit

- Key OFF.

- Disconnect the engine coolant temperature sensor connector.

- Install Rotunda Breakout Box 007-00033, or equivalent with Rotunda Breakout Box Adapter 007-00053 (leave the PCM disconnected).

- Measure the resistance between SIGRTN BOB Pin 46 and the SIGRTN wire at the engine coolant temperature sensor connector.

- Is the resistance less than 5 ohms?

YES -- SERVICE the ECT wire to PCM.

NO -- SERVICE the SIGRTN wire to the PCM.