U0159

Lost Communication With Parking Assist Control Module A

Network / Communication Network/Communication CAN Bus Communication 🟡 Moderate — Fix within a week ⚠️ Drive with Care
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What This Actually Means

In plain language — no jargon

Your car's main computer has lost its connection to the parking assist module, like a walkie-talkie losing signal. The parking assist features won't work until communication is restored.

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Symptoms You May Notice

3 known symptoms for this code
Parking assist system inoperative or disabled
Warning light illuminated on dashboard
Loss of parking sensors or camera display
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU sends periodic CAN bus messages to the parking assist control module and monitors for acknowledgment responses. If no valid messages are received within a set timeframe (typically 100-500ms), a communication timeout is logged. The ECU tracks message integrity through checksums and sequence counters.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
CAN Bus Response Time 50-200 milliseconds No response for >500ms or repeated timeouts
Message Checksum Validity Checksum matches calculated value Checksum mismatch or corrupt data frames
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Battery terminals and connectors
Clean corrosion from battery posts and check all ground connections; loose grounds cause CAN bus communication failures.
2
CAN bus wiring and connectors
Inspect the CAN bus harness between the main ECU and parking assist module for damaged insulation, loose pins, or corroded connectors.
3
Parking assist control module
If wiring and power are good, the module itself may have failed and require replacement or reprogramming at a dealer.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code U0159 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.

Safety note: OBD-II codes identify the system or circuit where a fault was detected — they do not always identify the exact failed component. A professional mechanic using live sensor data will diagnose the root cause more accurately than replacing parts based on the code alone.
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How to Clear Code U0159

What happens after you fix the fault

Once the fault is repaired, U0159 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.

The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.

✅ Safe to Clear When
  • Fault has been diagnosed and repaired
  • You want to confirm the repair worked
  • Code appeared after a sensor was cleaned
⚠️ Do Not Clear When
  • Preparing for an emissions/PUC test
  • Root cause is still undiagnosed
  • Check engine light is flashing
Emissions test note: Clearing codes resets OBD readiness monitors. Most vehicles need 50–100 km of mixed driving before monitors complete. Do not clear codes immediately before an emissions or PUC inspection.