C2339

Code

Generic C — Chassis

ABS/ESC Module Communication Fault

Brand: Generic

Type: C — Chassis

Views: UK: 12 EN: 28 RU: 18

AI status

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Page language: EN

Causes

Open, shorted or corroded wiring/connectors to the ABS/ESC module
Poor power supply or ground to the ABS/ESC module (low battery, blown fuse, bad relay)
Faulty ABS/ESC module or internal electronics
CAN (or other vehicle network) bus fault such as short to voltage/ground or missing termination
Intermittent wiring harness damage (chafing, water intrusion)
Software/configuration mismatch or failed module programming

Symptoms

ABS and/or ESC (traction control) warning lamp illuminated
Possible loss of ABS/ESC functions (no ABS or traction control intervention)
Reduced driving stability features or drivability limp mode in some vehicles
Stored communication and related ABS codes in memory
Intermittent or permanent faults depending on wiring/connection condition

What to check

Read all stored codes and freeze frame with a capable scan tool; log related U/C codes
Attempt to communicate with the ABS/ESC module with the scan tool (identify if module responds)
Inspect ABS module connectors and harness for corrosion, water, damage and secure connection
Check battery voltage (key on, engine off) and charging system; verify fuses/relays supplying ABS module
Measure power and ground at the ABS/ESC module connector
Check CAN bus for presence of frames using a diagnostic tool or oscilloscope

Signal parameters

Recessive CAN state: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V
Dominant CAN state: typical CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2.0 V)
Expected bus termination resistance between CAN_H and CAN_L ≈ 60 ohms (two 120 Ω terminators in parallel)
ABS/ESC module supply voltage (key on) typically 11–14.5 V; ground resistance < 0.5 Ω
No valid CAN frames from ABS/ESC module visible if module not communicating

Diagnostic algorithm

Connect a diagnostic scan tool; record C2339 plus any related U‑codes and freeze frame data. Note whether ABS/ESC module is listed and responds.
Verify battery voltage and charging system. Confirm fuses/relays for ABS/ESC power are present and not blown; inspect fuse box for corrosion.
Visually inspect ABS/ESC module connector and harness for corrosion, bent pins, water ingress or physical damage. Secure connector and re-check communications.
With key on, measure supply voltage and ground at the ABS/ESC module connector. If power/ground missing or intermittent, trace and repair circuit before further testing.
Check CAN bus operation: use a scope or scan tool to confirm CAN_H/CAN_L voltages and presence of frames. Measure termination resistance between CAN_H and CAN_L (~60 Ω).
If CAN bus fault found, isolate sections: disconnect other nodes (where safe) to see if a specific module or segment causes bus failure. Repair/replace faulty wiring or module.
Perform wiggle/torque tests on harness and connectors while monitoring communications to find intermittent faults.
If wiring, power and bus are good and module still does not respond, consult manufacturer reprogramming/recall/TSB information. Consider replacing or reprogramming the ABS/ESC module as directed.
After repair, clear codes and perform a test drive or network stress test to confirm fault does not return.

Likely causes

Loose, corroded or disconnected connector at the ABS/ESC module
Blown fuse or missing power/ground to the ABS/ESC module
CAN bus open or failed termination resistors
Damaged communication wiring (pinched/chafed harness)
Failed ABS/ESC control module

Fault status

⚠️ Status

ABS/ESC module communication fault — module not responding or intermittent on vehicle network (CAN).

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

Repair manuals

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