Code
C181D00
HYUNDAI
C — Chassis
CAN Time-Out EVP
Views:
UK: 14
EN: 14
RU: 15
AI status
Completed
Completed
100%
Causes
- Open, short or high resistance in CAN_H/CAN_L wiring between modules
- Faulty or loose connector at the EVP or at a junction on the CAN bus
- Loss of power or ground to the EVP module (blown fuse, corroded ground)
- Faulty EVP module (internal failure) or corrupted firmware
- Faulty ABS/ESC or other gateway module that reads EVP messages
- Intermittent CAN bus interference or missing termination resistor
Symptoms
- ABS/ESC warning lamp and/or brake system warning illuminates
- Reduced or degraded brake assist (harder pedal) if vacuum assist affected
- Traction control or stability control warnings
- Stored communication/time-out DTCs and possibly other related codes
- Intermittent or permanent loss of EVP function (pump not operating)
- Possible vehicle limp or degraded driveability depending on system
What to check
- Connect a scan tool; read and record all DTCs and freeze frame data from ABS/ESC, EVP and gateway modules
- Visually inspect EVP connector, pins and harness for corrosion, water intrusion, damage or loose pins
- Verify EVP module supply voltage and ground with ignition ON (battery voltage present, good ground)
- Check fuses and relays related to EVP and ABS circuits
- Measure CAN bus idle voltages and differential with a multimeter and/or oscilloscope
- Check CAN termination resistance (approx. 60 ohms between CAN_H and CAN_L)
Signal parameters
- Battery supply to EVP: ~11–14.5 V with ignition ON/cranking
- CAN bus idle (recessive): CAN_H ≈ 2.5–2.9 V, CAN_L ≈ 2.1–2.5 V (each referenced to chassis)
- CAN bus dominant state: CAN_H ≈ 3.5–4.5 V, CAN_L ≈ 0.5–1.5 V (differential ~2 V+)
- Termination resistance: ~60 ohms measured across CAN_H and CAN_L (two 120Ω in parallel)
- Expected repetitive message timing: EVP transmit interval and watchdog/heartbeat present — verify with known-good trace (oscilloscope/scan tool)
Diagnostic algorithm
- Retrieve all related codes from ABS/ESC, EVP and gateway modules; record freeze frame and occurrences.
- Clear codes and attempt to reproduce. Note whether code returns immediately, intermittently, or only under certain conditions.
- Perform a detailed visual inspection of the EVP connector and the CAN wiring harness for damage, corrosion, or water entry.
- With ignition ON, verify EVP power and ground at the module connector. Repair poor ground or restore fuse/relay as needed.
- Measure CAN_H and CAN_L voltages with key ON. If voltages are outside expected idle range, isolate wiring and check for shorts to Vbatt or ground.
- Use an oscilloscope or CAN bus analyzer to capture signals while operating the vehicle; check for ECG/heartbeat frames from the EVP and note timing/absence.
- Measure termination resistance across CAN_H and CAN_L. If termination is open or out of spec, locate missing/failed terminating resistor(s) or faulty module.
- Disconnect the EVP module and observe whether the bus recovers or other modules report different behavior (do this only per vehicle service instructions).
- If wiring and power/ground are good, consider reflashing module software per manufacturer bulletin; if issue persists, replace the EVP or the module indicated by diagnostics.
- After repair, clear codes and road-test to confirm communication is restored and no related DTCs return.
Likely causes
- Loose or corroded connector at the EVP
- Damaged CAN bus wiring (chafing, pinched, short to battery/ground)
- Blown fuse or bad ground supplying the EVP
- Failed EVP module or module that relays EVP messages
- Missing/failed CAN termination or interference from aftermarket device
Fault status
Status
CAN time-out: No/late communication received from Electronic Vacuum Pump (EVP) module on the CAN bus.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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