U0159 is a generic OBD-II network communication diagnostic trouble code indicating that communication with the Parking Assist Control Module "A" (PACM-A) has been lost. The module communicates with other vehicle control modules through the vehicle communication network and manages or processes information used by the parking-assistance system. 0
The exact module name, location, sensor configuration, communication network, and diagnostic procedure vary by manufacturer, model, and model year. On some vehicles the parking-assist module may be located near the rear of the vehicle or trunk area, while the network architecture can differ between applications. Always use vehicle-specific service information for final diagnosis. 1
U0159 Code Details
Code: U0159
Meaning: Lost Communication With Parking Assist Control Module "A"
Type: Generic OBD-II Network Communication Code
Main System: Parking Assist / Vehicle Communication Network
Symptoms of U0159
- Parking assist system may become unavailable.
- Parking sensors may stop providing warnings.
- A "Service Park Assist" or similar warning may appear.
- Parking-distance information may disappear from the display.
- Audible parking warning tones may be unavailable.
- Multiple communication-related DTCs may be stored.
- The scan tool may be unable to communicate with the parking assist module.
- Intermittent parking-assistance operation may occur.
Common Causes of U0159
- Low battery or system voltage.
- Blown fuse supplying the parking assist module.
- Missing module power supply.
- Poor or damaged module ground.
- Open CAN High or CAN Low circuit.
- Short circuit in the communication wiring.
- Loose or corroded electrical connector.
- Damaged wiring near the bumper or rear of the vehicle.
- Water intrusion into connectors or wiring.
- Another control module interfering with the CAN network.
- Faulty Parking Assist Control Module.
- Module software or configuration problem on some applications.
How Serious Is U0159?
U0159 is generally a moderate communication fault. It normally affects parking-assistance functions rather than basic engine operation, but the loss of parking sensors or distance warnings can reduce driver awareness of nearby obstacles.
The vehicle may remain operational, but the parking-assistance system should not be relied upon until the fault is repaired.
Can You Drive With U0159?
In most cases, the vehicle can still be driven because U0159 primarily affects the parking-assistance system. However, parking sensors, distance displays, audible warnings, or automated parking functions may not operate. The driver must therefore rely on normal visual checks and mirrors until the system is restored.
How to Diagnose U0159
1. Scan All Control Modules
Perform a complete vehicle scan and record U0159 together with all other stored or active communication, voltage, body, and chassis codes. If several modules report communication problems, investigate the common network or power supply before replacing the parking-assist module.
2. Check Battery Voltage
Verify battery condition and system voltage. Low voltage can cause control modules to reset or temporarily disappear from the vehicle network. Some manufacturer procedures specify a normal operating voltage range before continuing diagnosis. 2
3. Check Parking Assist Fuses
Use the vehicle-specific fuse diagram to identify the fuses supplying the Parking Assist Control Module. If a fuse is blown, determine the cause of the excessive current before replacing it.
4. Test Module Power and Ground
Check all required power feeds and ground circuits at the parking-assist module. Loss of power or ground is one of the important causes to investigate before condemning the module. 3
5. Inspect the Module Connector
Inspect the connector for corrosion, water contamination, loose terminals, bent pins, damaged locks, and poor terminal tension. Pay particular attention to wiring exposed to moisture or physical damage near the rear bumper.
6. Check CAN Communication
Inspect the CAN High and CAN Low circuits for opens, shorts, high resistance, damaged insulation, or poor connections. The exact CAN network and wiring path must be determined from the vehicle wiring diagram.
7. Determine Whether the Module Is Online
Use a professional scan tool to determine whether the parking-assist module responds to communication requests. If the module communicates normally but U0159 is stored as history, the fault may be intermittent. If the module does not respond, continue testing its power, ground, and network circuits. 4
8. Check for Software or Configuration Issues
Some vehicle applications can develop U0159 because of module software or network-management issues. Check manufacturer technical service information for applicable software updates or service procedures before replacing the module.
U0159 Oscilloscope Signal Patterns
An oscilloscope can be useful when U0159 is suspected to be caused by an intermittent or distorted CAN communication signal. It is particularly helpful when power, ground, and continuity checks appear normal but communication still drops out.
Normal / Active
Normal: Consistent CAN communication activity with clean signal transitions.
Abnormal / Distorted
Abnormal: Noise, distortion, irregular transitions, or intermittent network activity.
Inactive / No Communication
Inactive: Expected network communication activity is absent at the tested network point.
Important: These are simplified diagnostic illustrations, not manufacturer-specific waveform specifications. Actual CAN High and CAN Low voltage levels, timing, and network behavior must be compared with the specifications for the exact vehicle.
U0159 Diagnostic Signal Flow
↓
Parking Assist Control Module (PACM-A)
↓
CAN Communication Network
↓
BCM / IPC / Other Control Modules
↓
Driver Parking Warnings & Distance Information
U0159 OBD Live Data
Available parameters depend on the vehicle and scan tool. Where supported, useful information may include parking-assist module communication status, parking sensor status, vehicle speed, system voltage, obstacle-distance information, and parking-assist system status.
Live data should be compared with physical electrical measurements because an intermittent CAN or connector problem may not appear during a stationary scan.
Common Repairs for U0159
- Repair missing power to the parking-assist module.
- Repair poor or damaged module ground.
- Replace a failed fuse after identifying the cause.
- Repair damaged CAN High or CAN Low wiring.
- Repair corroded or loose connectors.
- Repair damaged wiring near the bumper or trunk area.
- Correct water intrusion.
- Repair another module that is disrupting the CAN network.
- Update or reprogram the parking-assist module when a manufacturer procedure applies.
- Replace the Parking Assist Control Module when internal failure is confirmed.
U0159 Repair Cost
- Electrical/network diagnosis: approximately $100–$200+.
- Fuse or wiring repair: approximately $75–$300+.
- Connector/terminal repair: approximately $80–$250+.
- Parking-assist module repair: approximately $150–$600+.
- Module replacement and programming: approximately $400–$1,500+ depending on vehicle.
These are general estimates only. Actual costs vary according to vehicle model, module type, parts availability, labor rates, and programming requirements.
Common Repair Mistakes
- Replacing the parking-assist module before checking power and ground.
- Ignoring low battery voltage.
- Failing to inspect connectors near the bumper or trunk.
- Replacing the module without testing CAN communication circuits.
- Assuming every stored U-code means the module itself has failed.
- Ignoring other communication codes stored in different modules.
- Failing to check for applicable manufacturer software updates.
- Installing a replacement module without completing required programming or configuration.
Related OBD-II Codes
- U0100 – Lost Communication With ECM/PCM.
- U0121 – Lost Communication With Anti-Lock Brake System Module.
- U0140 – Lost Communication With Body Control Module.
- U0150 – Lost Communication With Gateway Module "A".
- U0155 – Lost Communication With Instrument Panel Cluster.
- U0156 – Lost Communication With Information Center Module.
- U0157 – Lost Communication With Telematics Control Module.
- U0158 – Lost Communication With Telematics Control Module.
FAQ About U0159
Can a weak battery cause U0159?
Yes. Low system voltage can cause the parking-assist module or other control modules to reset or temporarily stop communicating.
Can a CAN wiring problem cause U0159?
Yes. An open, shorted, damaged, or poorly connected CAN circuit can interrupt communication with the Parking Assist Control Module.
Does U0159 mean the parking assist module is bad?
No. Power, ground, fuses, connectors, and CAN communication circuits should be tested before replacing the module.
Can U0159 disable parking sensors?
Yes. When communication with the parking-assist module is lost, parking sensor warnings, distance information, or other parking-assistance functions may become unavailable.
Can an oscilloscope help diagnose U0159?
Yes. An oscilloscope can help identify abnormal CAN activity, electrical noise, distortion, or intermittent communication when a network fault is suspected.
Does a replacement parking assist module need programming?
Some vehicles require programming, configuration, coding, or initialization after replacement. The exact procedure depends on the manufacturer and vehicle.
Final Takeaway
U0159 is a generic OBD-II network communication code indicating lost communication with the Parking Assist Control Module "A".
A systematic diagnosis should begin with battery voltage, fuses, module power and ground, connectors, and CAN communication circuits. The parking-assist module should only be replaced after its electrical supply and network communication have been properly verified.