Code
U1113
PEUGEOT
U — Network/User
Fault in communication with the ABS/ESP ECU on the CAN: No signal
Views:
UK: 1
EN: 1
RU: 4
AI status
Completed
Completed
100%
Causes
- ABS/ESP ECU not powered or has internal fault
- Open or short in CAN High/Low wiring to the ABS/ESP ECU
- Corroded/damaged connector or poor pin contact at the ABS/ESP ECU
- Missing or faulty CAN termination (open or incorrect resistance)
- Blown fuse or loss of ground/supply to the ABS/ESP ECU
- Another module pulling down the CAN bus or producing noise
Symptoms
- ABS and/or ESP warning lamp illuminated
- Loss of ABS/ESP functionality (braking assistance or stability control disabled)
- Possible loss of related functions (traction control, brake light indicators)
- Intermittent or permanent failure of speed-related messages to other modules
- No ABS/ESP data visible on diagnostic scanner or CAN trace
What to check
- Scan vehicle for current and historic codes from all ECUs and note freeze-frame data
- Visual inspection of ABS ECU connector and harness for corrosion, damage, pins pushed out or water ingress
- Check fuses and relays that feed ABS/ESP ECU power and accessory supplies
- Measure supply voltage and ground at ABS ECU pins with ignition on
- Check CAN bus wiring continuity and for short to battery or ground
- Measure CAN termination resistance across CAN_H and CAN_L (typical ~60 Ω)
Signal parameters
- CAN_H idle voltage ≈ 2.5 V (single-ended)
- CAN_L idle voltage ≈ 2.5 V (single-ended)
- Differential idle voltage ≈ 0 V, dominant ≈ 2 V differential
- Typical ABS message period: often 10–100 ms (varies by model)
- CAN data rates commonly 250 kbps or 500 kbps depending on vehicle
- Termination resistance between CAN_H and CAN_L ≈ 60 Ω (two 120 Ω terminators in parallel)
Diagnostic algorithm
- Read and record codes from all modules, note any related U- or B- codes. Clear codes and see if U1113 returns.
- Attempt to monitor CAN traffic with a diagnostic tool. Confirm absence of ABS ECU messages (check expected message IDs and frequency from wiring diagram/service info).
- Perform visual inspection at ABS ECU connector; disconnect and inspect pins for damage or corrosion. Reconnect and wiggle-test while monitoring CAN to check for intermittent contact.
- Check ABS ECU +12V (or ignition supply) and ground pins with DMM. Verify proper voltages with ignition ON and engine running as required.
- Measure CAN_H and CAN_L voltages at the ABS ECU connector and elsewhere on the network. Compare to expected idle levels and look for shorts to supply or ground.
- Measure end-to-end CAN termination resistance (engine off). If not ~60 Ω, locate missing or damaged terminator(s).
- If bus appears inactive, isolate segments: disconnect ABS ECU and check if bus activity changes or other modules recover; reconnect to see if ABS ECU loads the bus.
- Inspect and test related fuses/relays and check for chassis ground continuity near ABS unit.
- If wiring and power/ground are good but no messages, consider reflashing/config check or replacement of ABS ECU per manufacturer procedures. Follow pairing/security steps if ECU replaced.
- After repairs, clear codes and perform road test to confirm ABS/ESP communication restored and no recurrence.
Likely causes
- Damaged connector or wiring between ABS ECU and CAN bus (most common)
- Blown fuse or lost power/ground to ABS ECU
- Failed ABS/ESP ECU (internal hardware failure)
- Open or incorrect CAN termination resistor
- Intermittent short or high-resistance connection causing bus inactivity
Fault status
Status
No CAN communication detected from ABS/ESP ECU (U1113)
Repair difficulty: Medium
Diagnostic time: 1-3 hours
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