Code
C1600
Generic
C — Chassis
Chassis Control Module Communication Fault
Views:
UK: 6
EN: 25
RU: 12
AI status
Completed
Completed
100%
Causes
- Faulty CCM (module internal failure)
- Loss of module power or ground
- Open, shorted, or corroded CAN/LIN bus wiring or connectors
- Improper CAN/LIN termination or bus voltage out of range
- Intermittent connector contact / damaged pins
- Faulty or misconfigured gateway / other control module interfering with network
Symptoms
- Stored C1600 and possibly related network/communication codes
- ABS, traction control, stability control warnings or reduced functionality
- Message center warnings about communication or module unavailable
- Intermittent or permanent loss of chassis features
- Modules appear offline on a scan tool or network data absent
- Recurring/returning fault after clearing
What to check
- Scan all modules, record freeze-frame data and related DTCs (look for other U- or C-codes)
- Confirm vehicle battery voltage and key-on power supplies to CCM
- Inspect CCM connector and wiring for corrosion, bent pins, or damage
- Measure CAN/LIN bus idle voltages with ignition ON (see signal parameters)
- Measure bus resistance across CAN_H and CAN_L with ignition OFF (approx. 60 ohms nominal for typical dual-terminated CAN)
- Check for shorts to battery or ground between CAN_H/CAN_L and chassis
Signal parameters
- CAN bus (recessive state): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (each)
- CAN bus (dominant state): CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V, differential ≈ 2 V
- Idle CAN differential should be near 0 V (both ~2.5 V) until traffic is present
- Termination resistance (ignition OFF): ~60 ohms measured across CAN_H and CAN_L (two 120 Ω terminators in parallel)
- LIN/K-Line/other serial: idle voltages depend on network (consult wiring diagram and spec sheet)
Diagnostic algorithm
- Connect scan tool and retrieve all chassis and network codes; note freeze frame and module status.
- Clear codes, then attempt to reproduce. Determine if fault is permanent or intermittent.
- Visually inspect CCM connector and harness; repair any damaged pins or corrosion.
- Verify CCM supply voltage and ground with key ON and cranking; repair any power/ground faults.
- With ignition ON, measure CAN_H and CAN_L idle voltages at the CCM connector and at other nodes; compare values and look for a node pulling the bus low/high.
- With ignition OFF, measure DC resistance across CAN_H and CAN_L at the same points to confirm termination (~60 Ω).
- Use an oscilloscope to view CAN waveforms while operating a module that should communicate; look for dominant/stuck bits, noise, or missing messages.
- Disconnect non-essential modules or aftermarket devices one at a time (or isolate wiring segments) to find the offending device or short.
- If wiring and voltages are good, check for TSBs/firmware updates; attempt a module reprogram or soft reset per manufacturer procedure.
- Replace the CCM only after confirming wiring, power/ground, and network integrity. Relearn/initialize as required after replacement and recheck for faults.
Likely causes
- Poor power/ground to the CCM (missing feed or bad ground)
- Damaged or shorted CAN high/low wiring or connector corrosion
- Bus termination resistance incorrect (open or shorted termination resistors)
- Other module driving the bus into error (bus-off) or stuck dominant
- Intermittent connector or pin contact at the CCM
Fault status
Status
Chassis Control Module communication fault — CCM is not communicating correctly on the vehicle network. Check power/grounds, wiring, and bus integrity.
Repair difficulty: Medium
Diagnostic time: 1-4 hours
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