Chrysler 66 CCD Bus Communication Fault
How to read it
Code 66 reads as 6 flashes, pause, 6 flashes on the check-engine light. Cycle the ignition key on, off, on, off, then leave it on with the engine off, and count the flashes on the power loss or check-engine light.
New to flash codes? The How to Read Chrysler OBD-I Codes with the Key Cycle walks through the test and what the numbers mean. The general OBD-I guide covers the rest.
What does Chrysler code 66 mean?
CCD Bus Communication Fault
Common causes of 66
- Open or shorted CCD bus wires between modules
- Failed body controller or transmission controller
- Missing or poor module ground on the bus
- Corroded bus connector pins
- No CCD message from the transmission or body controller
How to fix 66
- Check whether other modules still communicate on the bus
- Inspect the CCD bus wiring and connectors for opens and shorts
- Disconnect modules one at a time and recheck communication
- Verify module powers and grounds before replacing a module
- Repair the bus wiring before replacing any controller
- Clear the code and confirm data exchange resumes
Sources and review
Review: qualified. Read the source limits below.
- Chrysler OBD-I trouble codes, model and year page
live reference page (troublecodes.net)
Supports: code identity and Chrysler meaning
Fetched directly from the linked model page. Single publisher, so the record is qualified, not verified. Causes and check order are curator-written from the circuit the code names.
- Chrysler OBD-I trouble codes, model and year page
live reference page (troublecodes.net)
Supports: code identity and Chrysler meaning
Fetched directly from the linked model page. Single publisher, so the record is qualified, not verified. Causes and check order are curator-written from the circuit the code names.
Last updated 2026-10-10.
Report a correction for 66. Include your vehicle, the issue and a source if you have one.