Code
P1694
PONTIAC
P — Powertrain
No CCD Messages Received From ECM
Views:
UK: 31
EN: 34
RU: 44
AI status
Completed
Completed
100%
Causes
- Faulty or non‑powered ECM
- Open, shorted or damaged communication wiring between ECM and cluster or bus
- Blown fuse or loss of ECM power/ignition feed
- Poor or corroded connector or ground
- Faulty instrument cluster or receiving module
- Aftermarket device or module interfering with the data bus
Symptoms
- Malfunction Indicator Lamp may be on or unavailable
- Engine data (RPM, coolant temp, check engine lamp) may be missing on dash
- Possible drivability issues if other modules rely on ECM data
- Diagnostic scanner reports no response or missing ECM messages
- Other modules reporting communication-related DTCs
What to check
- Connect a full‑function scan tool and attempt to communicate with the ECM and other modules
- Check for stored U‑ or P‑codes that indicate network faults (e.g., U0100, P0600)
- Visually inspect fuses related to ECM and instrument cluster; verify fuse continuity and power with key ON
- Inspect ECM and instrument cluster connectors for corrosion, bent pins, or water intrusion
- Wiggle test harnesses while monitoring bus activity to find intermittent faults
- Check chassis and engine grounds and ECM power feed voltages with key ON/engine OFF
Signal parameters
- Normal: periodic digital messages from ECM on the vehicle communication bus; consistent message timing and amplitude (monitor with scan tool or oscilloscope)
- Fault: no message frames from ECM, or bus held to constant voltage (short to battery or ground)
- Use a scan tool to watch for message IDs and update rates; absence of ECM message IDs indicates upstream fault
Diagnostic algorithm
- Verify and record the DTC and any related U/P codes with a scan tool. Clear codes and attempt to re‑read to confirm repeatable condition.
- Confirm other modules respond to the scan tool. If no modules respond, verify scanner/configuration and vehicle power/ignition circuits.
- Check ECM power and ground circuits: inspect related fuses, measure supply voltage to ECM with key ON, and verify good ground continuity to chassis.
- Visually inspect communication wiring and connectors between ECM and instrument cluster/body modules for damage, corrosion, or disconnection. Repair any damaged connectors or wires.
- Using a scan tool or oscilloscope, check the communication bus for activity. If bus is inactive, probe for short to battery or ground on communication lines.
- If bus activity is present but no ECM messages, attempt direct communication with the ECM at its connector. If the ECM does not respond but other modules do, suspect ECM internal failure.
- Disconnect any recently installed aftermarket devices that interface with power or the data bus and retest.
- Repair wiring, connectors, or replace faulty fuses as found. If ECM is determined to be non‑communicative after wiring and power/ground verified, consider ECM replacement or repair per factory procedures.
- After repairs, clear codes and perform a full system recheck and road test to confirm proper communication and operation.
Likely causes
- Blown fuse or ECM power/ground missing
- Damaged/shorted communications wiring or connector corrosion between ECM and cluster
- ECM internal failure (not transmitting)
- Faulty instrument cluster or other module not listening to bus
- Aftermarket alarm/remote start or repower splice on communication line
Fault status
Status
No CCD messages received from ECM — the instrument cluster/module is not receiving expected communications from the Engine Control Module.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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