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U0073ToyotaToyota Prius HubAll Toyota U0073Critical Severity

U0073 on Toyota Prius

Control Module Communication Bus A Off

Factory diagnostic protocol and troubleshooting wire for fault code U0073 specifically for the Toyota Prius (2020–2026, 2.0L 4-Cyl Hybrid (M20A-FXS 196HP) / Prius Prime PHEV (220HP)).

Verified OEM Telemetry & Field Repair Tree
Toyota Prius2020–2026
Toyota Prius
EV2.0L 4-Cyl Hybrid (M20A-FXS 196HP) / Prius Prime PHEV (220HP)
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
Prius SAE Mode $01
ECU Network Bus
500 kbps CAN-FD
ISO 15765-4 Compliant
Drivability Status
Not Recommended
Critical urgency level
Est. Repair Cost
$150 - $850 (DIY: $40 - $200)
Parts & Labor DIY
Check U0073 On Another Toyota Model:
Diagnose U0073 on Specific Prius Model Year:

1. Symptoms of U0073 on Toyota Prius

When the Engine Control Module (ECM/PCM) on your Toyota Prius (2.0L 4-Cyl Hybrid (M20A-FXS 196HP) / Prius Prime PHEV (220HP)) logs fault code U0073, drivers commonly observe:

StabiliTrak / Traction / ABS / Engine warning lights lit on Toyota Prius (2.0L 4-Cyl Hybrid (M20A-FXS 196HP) / Prius Prime PHEV (220HP))
Transmission shifting harshly or refusing to shift out of 2nd gear on Toyota Prius (2.0L 4-Cyl Hybrid (M20A-FXS 196HP) / Prius Prime PHEV (220HP))
No communication with TCM, ABS, or BCM on Toyota Prius (2.0L 4-Cyl Hybrid (M20A-FXS 196HP) / Prius Prime PHEV (220HP))
Engine may refuse to crank on Toyota Prius (2.0L 4-Cyl Hybrid (M20A-FXS 196HP) / Prius Prime PHEV (220HP))
Toyota Prius OBD-II Port Location
The 16-pin diagnostic connector is located Under driver side dashboard near A-pillar trim. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Toyota Prius

Historical warranty claims and technical repair bulletins for Toyota Prius point to the following failure distribution:

55%
Loose or corroded ground connection on transmission or frame (Toyota OEM Part)
25%
Faulty Transmission Control Module (TCM) or ABS module pulling bus down (Toyota OEM Part)
12%
Poor connection at large body-to-chassis pass-through harness connector (Toyota OEM Part)
8%
Aftermarket accessory (remote starter, GPS tracker, cheap OBD scanner) broadcasting invalid data (Toyota OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for Toyota Prius.

3. Step-by-Step DIY Repair Guide for Toyota Prius

01
Unplug All Aftermarket OBD-II Devices

Remove any aftermarket insurance dongles, GPS trackers, or scan tools plugged into the DLC port. on the Toyota Prius equipped with 2.0L 4-Cyl Hybrid (M20A-FXS 196HP) / Prius Prime PHEV (220HP).

Required Tool: None
02
Inspect Frame and Transmission Ground Straps

Inspect braided ground straps on engine and transmission. Clean all contact surfaces to bare metal. on the Toyota Prius equipped with 2.0L 4-Cyl Hybrid (M20A-FXS 196HP) / Prius Prime PHEV (220HP).

Required Tool: Wire Brush, Sockets
03
Perform Full Vehicle Network Topology Scan

Scan all modules on vehicle. Note which modules are online and which are offline to pinpoint the break in the network daisy-chain. on the Toyota Prius equipped with 2.0L 4-Cyl Hybrid (M20A-FXS 196HP) / Prius Prime PHEV (220HP).

Required Tool: Full-System OBD-II Diagnostic Scanner
04
Check Terminating Resistance (60 Ohms)

Verify 60 ohms across Pins 6 and 14 with battery disconnected. on the Toyota Prius equipped with 2.0L 4-Cyl Hybrid (M20A-FXS 196HP) / Prius Prime PHEV (220HP).

Required Tool: Multimeter
05
Clear All System DTCs & Road Test

Clear DTCs from all modules and road test to verify error-free network transmission. on the Toyota Prius equipped with 2.0L 4-Cyl Hybrid (M20A-FXS 196HP) / Prius Prime PHEV (220HP).

Required Tool: Scan Tool
Recommended Parts & Testing Tools

Equipment for Diagnosing Toyota Prius (U0073)

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Direct-Fit Replacement Part

Toyota Prius OEM Replacement Sensor

4.7 / 5.0 (Verified Fit)

Direct-fit replacement assembly engineered to OEM tolerances for Toyota Prius.

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Sensor Signal Voltage Meter

AstroAI Auto-Ranging Digital Multimeter

4.6 / 5.0 (Best Seller)

Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.

$29.99 Prime
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Top Mobile OBD-II Scanner

BlueDriver Bluetooth Pro OBDII Scan Tool

4.7 / 5.0 (50,000+ Reviews)

Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.

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Other Common Fault Codes on Toyota Prius

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Toyota Prius:

4. Toyota Prius U0073 FAQs

What causes code U0073 to trigger on a Toyota Prius?

On the Toyota Prius (2.0L 4-Cyl Hybrid (M20A-FXS 196HP) / Prius Prime PHEV (220HP)), U0073 is most frequently caused by Loose or corroded ground connection on transmission or frame or Faulty Transmission Control Module (TCM) or ABS module pulling bus down.

Where is the OBD-II port located on my Toyota Prius?

On the Toyota Prius, the 16-pin DLC diagnostic connector is located Under driver side dashboard near A-pillar trim. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.

Can I safely drive my Toyota Prius with code U0073?

No. Bus is shut down due to excessive transmission errors, leaving vehicle in unpredictable limp mode. Given that U0073 carries a Critical severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.