Fault Code U1113-87: No Communication with the ABS/ESP Control Unit
Has a vehicle entered your workshop with multiple brake system warning lights illuminated, and does the diagnostic equipment report fault code U1113-87?
This fault code indicates that a control unit is not receiving an expected message from the ABS/ESP system. The root cause may be a defect within the ABS/ESP module itself, but issues with the power supply, wiring, or CAN bus communication can also be responsible. The fault description commonly associated with this code is:
"Communication on the CAN with the ESP ECU: Absence of Communication."
When the vehicle is equipped with a Bosch 9.0 ESP Premium system, a defect within the ABS/ESP module may be the underlying cause.
Vehicles Equipped with the Bosch 9.0 ESP Premium
The Bosch 9.0 ESP Premium is an advanced ABS/ESP system designed for vehicles with sophisticated driver assistance technologies and is commonly found in premium vehicle segments.
Examples of applications include:
Audi
BMW
Bentley
Jaguar
Mercedes-Benz
Porsche
Symptoms Associated with Fault Code U1113-87
When the Bosch 9.0 ESP Premium module stops communicating on the CAN network, other control units lose access to essential vehicle data such as wheel speed and brake pressure information. This can result in a variety of symptoms, including:
- Cruise control malfunctions, including deactivation of the speed limiter.
- Incorrect or missing vehicle speed information.
- The automatic transmission entering limp-home mode.
- Additional communication faults in systems such as power steering.
- The ABS/ESP module being inaccessible during a network scan, preventing communication with the diagnostic tester.
- ABS, ESP, and brake system warning lights illuminating on the dashboard.
- Limited functionality or fault messages from systems that depend on ABS/ESP data, such as the electronic parking brake.
- Related fault codes stored in other control units, including the Gateway, engine ECU, and body or comfort control modules, indicating missing or invalid ABS/ESP data.
Diagnostic Recommendations
Fault code U1113-87 does not automatically mean that the ABS/ESP module is defective. A thorough diagnosis is essential to rule out wiring faults and power supply issues before condemning the module.
Perform a Complete Vehicle Scan
Carry out a network scan of all control units. If the ABS/ESP module is the only control unit that does not respond, the issue is likely local to the module itself or its associated wiring.
Inspect the Connector
Check the ABS/ESP module connector for:
- Water ingress
- Corrosion
- Damaged or displaced pins
- Poor terminal connections
- Verify Power and Ground Circuits Under Load
Refer to the manufacturer's wiring diagram to identify the correct pin assignments.
Measure:
- Permanent battery supply
- Ignition-switched supply
- Ground connections
Do not rely solely on a multimeter. Perform voltage drop testing under load using an appropriate test load to identify hidden resistance in power or ground circuits.
Check CAN Bus Communication
Use an oscilloscope to inspect the CAN High and CAN Low signals directly at the ABS module connector.
With the system powered down, also verify CAN network termination. In a typical high-speed CAN system, resistance between CAN High and CAN Low should measure approximately 60 Ω.
If all power supplies, ground circuits, and CAN signals are confirmed to be correct up to the connector, yet communication with the ABS/ESP module remains impossible, an internal defect in the Bosch 9.0 ESP Premium module becomes the most likely cause.
Repair Solution: Refurbishment of the Bosch 9.0 ESP Premium
Rather than purchasing an expensive new ABS/ESP unit, which often requires coding or programming, refurbishment of the original module is a practical and cost-effective alternative.
ACTRONICS offers a professional refurbishment service for the Bosch 9.0 ESP Premium. During the refurbishment process, defective and weakened electronic components are replaced. The unit is then thoroughly tested using an advanced End-of-Line test setup that fully simulates real vehicle operation.
Why Choose Refurbishment?
Plug-and-Play Solution
Because the vehicle's original module is repaired, all vehicle-specific coding and parameters are retained. In most cases, no additional programming is required.
Cost-Effective Repair
Refurbishment is significantly more affordable than purchasing a new OEM replacement unit.
Quality and Sustainability
Refurbishing the original module reduces electronic waste and extends the service life of the component. Every refurbished unit is supplied with a standard 2-year warranty.
Need a Repair?
If your diagnosis confirms fault code U1113-87 and a defective Bosch 9.0 ESP Premium module, simply register the unit for refurbishment with ACTRONICS. This enables a fast, reliable repair and helps get the vehicle safely back on the road with minimal downtime.