Code
P1694
DODGE
P — Powertrain
No CCD Messages Received From ECM
AI status
Completed
Completed
100%
Causes
- Blown or corroded fuse supplying the ECM or data bus
- Poor or missing ground(s) for the ECM or receiving module
- Open, shorted or corroded wiring/connectors on the CCD data circuit
- Failed or intermittent ECM (no data transmission)
- Faulty instrument cluster / body control module (incorrectly reporting no data)
- Aftermarket radio, alarm or other device interfering with the data bus
Symptoms
- Malfunction indicator lamp or communications warning
- Instrument cluster or body modules display wrong or missing data
- Engine may enter limp mode or exhibit drivability issues if ECM commands are not received
- No live engine data available on a scan tool from the ECM
- Intermittent or permanent loss of features controlled via the data bus (gauges, displays, remote functions)
What to check
- Use a scan tool: attempt to communicate with the ECM and check for ECM presence and CCD message traffic
- Verify battery voltage and proper charging system operation
- Check relevant fuses and fusible links for ECM and bus power/ignition feed
- Visually inspect ECM and receiving module connectors for corrosion, bent pins or water intrusion
- Perform wiggle tests on harnesses while monitoring communication for intermittent restoration
- Measure resistance/continuity of data wire between modules (with battery disconnected when checking continuity)
Signal parameters
- CCD network should show regular data message traffic when ignition is ON; absent or frozen bus indicates fault
- Data line may be idle at battery potential with short pulses when active; verify expected activity with a scope
- Continuity between module CCD/data pins should be low ohms (no open circuit); high resistance indicates corrosion
- Check supply and ground circuits to ECM: steady battery voltage present at power feed, solid ground continuity to chassis
Diagnostic algorithm
- Connect a scan tool and confirm the P1694 is current or stored and observe 'no ECM messages' condition. Attempt to communicate directly with the ECM.
- Check battery voltage; low supply can cause network comms to fail. Recharge or replace battery if needed.
- Inspect and test fuses related to the ECM and body/cluster modules. Replace any blown fuses and retest communications.
- Visually inspect ECM and receiving module connectors and harness routing for obvious damage, corrosion, water intrusion or rodent damage.
- Backprobe the CCD/data pin at the ECM and at the receiving module. With ignition ON, look for data activity with a scan tool live data or an oscilloscope. No activity indicates ECM not transmitting or open/short on bus.
- If bus is inactive, check for shorts to ground or battery on the data line. Disconnect non-ECM modules one at a time (where service information permits) to isolate a faulty module dragging the bus down.
- Check grounds for ECM and affected modules for proper continuity to chassis. Repair any poor grounds.
- If wiring and grounds are good but no ECM messages, refer to manufacturer service information for ECM bench test or reprogramming. Do not replace the ECM without confirming it is the fault.
- After repairs, clear codes, cycle ignition and verify normal CCD message flow and that P1694 does not return.
Likely causes
- Open or corroded connector at ECM or body module
- Blown fuse to ECM or bus power/ignition feed
- Damaged CCD data wire between ECM and receiving module
- Failed ECM not transmitting CCD messages
- Ground circuit fault at ECM or receiving module
Fault status
Status
Module reports no CCD serial data messages received from the Engine Control Module (ECM). Communication between ECM and receiving module is missing or interrupted.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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