Code
C1569
ALFA ROMEO
C — Chassis
Communication error
AI status
Completed
Completed
100%
Causes
- Open, shorted, or intermittent wiring in CAN/LIN network
- Faulty or corroded connector(s) at control module(s)
- Blown fuse or loss of power/ground to a module
- Failed or unresponsive control module
- Missing or incorrect module programming/software mismatch
- Improper termination (missing/bad CAN bus resistors)
Symptoms
- One or more systems inoperative or intermittent (e.g., ABS, airbags, instrument cluster, body functions)
- Warning lights or messages on the instrument panel
- Modules not responding to diagnostic scan tool
- Intermittent faults that clear when battery disconnected or vehicle restarted
- Loss of specific functions controlled over the network
What to check
- Read all stored DTCs from all modules and note freeze-frame/occurrence data
- Check battery voltage (should be within normal range) and battery connections
- Inspect fuses and power/ground connections for the affected module(s)
- Visually inspect connectors and wiring for damage, corrosion, or poor seating
- Use scan tool to see which module(s) are not communicating
- Measure CAN_H and CAN_L voltages with ignition ON (or as specified)
Signal parameters
- CAN (idle recessive): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (dominant: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V)
- Differential CAN idle ≈ 0 V; dominant differential up to ≈ 2 V
- CAN bus termination resistance ≈ 60 ohms (two 120Ω in parallel)
- LIN idle: near battery voltage; dominant frames driven low ≈ 0.5 V
- Expected stable periodic message traffic on bus when engine/key ON
Diagnostic algorithm
- Connect a factory-level or capable aftermarket scan tool and record all stored and pending codes from every module. Note frequency and freeze-frame data.
- Attempt to communicate with the module(s) that report loss of communication. If entirely non-responsive, check power and ground at that module first.
- Check battery voltage and charging system; ensure stable supply during testing (use a charged battery or stable power supply).
- Inspect connectors and harnesses for physical damage, corrosion, or water ingress. Repair any damaged wiring or connectors.
- With ignition OFF, measure termination resistance across CAN_H and CAN_L at a convenient connector; expect ~60 ohms. If incorrect, isolate and find missing/shorted termination.
- With ignition ON, measure CAN_H and CAN_L voltages and verify waveform integrity with an oscilloscope. Look for missing frames, dominant states, excessive noise, or stuck lines.
- If intermittent, wiggle-test harness and connectors while monitoring bus for errors to locate intermittent connection faults.
- Isolate the fault by disconnecting modules one at a time (following manufacturer safety/procedure) to see when the bus returns to normal; this can identify the offending module or circuit.
- Check for relevant technical service bulletins or required software updates. Reprogram module(s) if a software mismatch is suspected.
- Replace or repair defective wiring/connectors or replace the faulty module only after confirming it is the root cause. Clear codes and road test to confirm repair.
Likely causes
- Damaged wiring harness between modules or to gateway module
- Loose or corroded connector at the suspected control module
- Battery voltage drops causing modules to reset
- Defective gateway or bus master module
- CAN bus short to battery or ground
Fault status
Status
Communication error on vehicle network detected. Modules failing to exchange required messages — inspect wiring, power/grounds, connectors, and module health/software.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
Repair manuals
Manual library for ALFA ROMEO
3
Browse 3 ALFA ROMEO manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.
ALFA ROMEO
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ALFA ROMEO: 2020
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Giulia
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